The film opens with Tamizh (Dhanush), his wife Yamuna (Samantha Ruth Prabhu) and his mother (Raadhika Sarathkumar) moving into a new home which is not very comfortable. Tamizh leaves them with his friend Kumaran (Sathish) after settling them in the new house in search of a job. All the companies are pleased with his resume but are hesitant to give him a job due to the occurrences in his past job. Finally, out of need, Tamizh becomes a worker in a roadside biriyani shop. He comes home for the night after he gets drunk. He then narrates the reason for him becoming like this through a series of flashbacks.
During his college days, Tamizh (a second year B. Com student), Kumaran, and Tamizh's cousin Aravind (Adith Arun) were inseparable friends. One day, Tamizh's mother tells him to go to the temple for a pooja. There he meets Hema (Amy Jackson), who is an architecture student, and immediately falls in love with her. He then follows her around and wins her heart and they both fall in love. For their first anniversary, Tamizh, Hema, Kumaran and Hema's friend Revathi go to Darjeeling. Tamizh was doing all this without the knowledge of his father and Aravind, for which Tamizh feels guilty. He decides that he will tell them both the truth once he goes back to Chennai. But in Darjeeling he is faced by Aravind, who followed him to see what he was up to and make him feel guilty. Aravind says he never wants to see Tamizh again and storms off. Then they both go to the rooms and Hema gives Tamizh a plan of their future house. Tamizh sees that there is no room for his parents in their new house. He asks Hema about this and she says they will not be staying with them. This infuriates Tamizh and they both fight, eventually leading to their breakup.
They both move on with their own lives. Tamizh joins the same Income tax office as his father and Hema gets married to Aravind. Tamizh also accepts to get married and marries Yamuna. He is deeply in love with Yamuna and forgets Hema, leaving her to be Aravind's wife. One day Tamizh's father returns home tense and shouts at his wife. The next morning, when Yamuna opens the bathroom door, it is found that Tamizh's father has hung himself. Everybody says that he stole a file from his office and calls him a thief. Tamizh is also suspended without pay and eventually asked to vacate their house by the landlord. First they go to Yamuna's place. But Yamuna's parents treat Tamizh poorly, so she suggests they go to a new home.
In the present Tamizh tries to gather information regarding his father in vain. At last, a close friend of his father sees Tamizh and says that his father once mentioned a bag of money. So Tamizh goes to see his boss Prakash Kumar (Jayaprakash), who tells him that he gave his father 5 crore rupees to safeguard as there was a raid in his house, and that when asked to return it he said he forgot where he kept them. Prakash Kumar thinks that he stole the money and takes an important file and threatens Tamizh's father to return the money to get the file. Tamizh remembers his father once arguing with Aravind, so he goes to see him about the money. Aravind denies any such thing. Later, Hema confronts Aravind about the money and in a drunk state he tells her that he took the money for his business and that he was about to return it once he was settled but Tamizh's father had unexpectedly committed suicide before that. Hema meets Yamuna in the temple and tells her the truth behind the money. So Tamizh visits Aravind's house when he is out and searches his house, where he finds agreement papers for a certain builders. Tamizh goes to that builders which was under construction as one of Aravind's men, collects details about the place, date and time of the deal closure, and convinces the dealer this year to be he has changed the time to 9 o'clock instead of 7. At 7, Tamizh goes to the place of making the deal where Aravind arrives with one crore of the money. Tamizh takes the money with him.
That night some people come to Tamizh's house to steal the money, but Tamizh wards them off. The next day, Tamizh gets informed by an anonymous caller about an income tax raid at his house. Tamizh gives the money to Kumaran to safeguard it who is intercepted by Aravind and takes back the money. Tamizh finds out the call list of Aravind and finds a number frequently called by Aravind. He find the address of the owner and finds that he has the other 4 crore to turn it into white. He beats him up and takes the money back. Aravind finds out about this and tries to safeguard the rest, becoming a mental patient in the process. He finally give the money back to Tamizh asking for his forgiveness. Tamizh goes to Prakash Kumar and says that he got the money and that he will give it to him to get his job and the file back. But Prakash Kumar reveals that he sold the file for fifty crores and that Tamizh take the 5 crore and close this issue. But Tamizh doesn't want it and tells him to accept his mistake. So Prakash Kumar sends some goons to finish Tamizh off when he was coming with his wife Yamuna, who is now pregnant, but he fights back. He later calls Prakash Kumar and tell him to see the news where his assistant (M. S. Bhaskar) is revealing that Prakash's corrupt activities. Tamizh then tells him that he gave his assistant the 5 crore to confess. Prakash Kumar is arrested while Yamuna gives birth to a baby boy. The film ends showing a happy Tamizh leaving for a job.Dhanush as Thamizh VijayraghavanSamantha Ruth Prabhu as Yamuna ThamizhAmy Jackson as Hema D'Souza AarvindK. S. Ravikumar as VijayraghavanRaadhika Sarathkumar as Thamizh's motherAdith Arun as ArvinthSathish as KumaranJayaprakash as Prakash KumarM. S. Bhaskar as Prakash Kumar's assistantSeetha as Aarvind's motherShan as VarunPoorthi Pravin as RevathiUday Mahesh as Jen Builders AgentVelraj as Ramalingam (cameo appearance)Andrea Jeremiah in a voice-over for Amy Jackson as Hema D'Souza
Following the success of Velaiilla Pattadhari (2014), Dhanush and Velraj announced that they would work together for another project during October 2014, and stated the film would not be a sequel to their previous film. In December 2014, actress Amy Jackson revealed via Twitter that she had been signed on to feature in the film. During the same month, Prabhu also joined the team, which reprised several crew members from the director's previous venture. Sathish was selected to play a supporting role, while K. S. Ravikumar and Raadhika Sarathkumar were signed on to play Dhanush's parents in the film.
The team began production in March 2015 without a title, and the project remained untitled until October 2015, a month before the film's release. It developed under the working title of VIP 2, and the team denied reports of it being titled Tea Kadai Raja and Thamizh Magan, before settling on Thanga Magan. The first schedule involved Dhanush and Amy Jackson, with the former shaving his beard to appear as a teenager in the portions. Scenes involving Samantha portraying Dhanush's wife were shot in May 2015, with the team recreating the effect of rainy backdrop in a studio in Chennai. Amy Jackson finished work in the film in June 2015, after filming sequences alongside the other two lead actors. The film completed its final schedule in July 2015 by canning a fight scene and montage shots, without the presence of Velraj, who had to prioritise his work as a cinematographer for another film, Paayum Puli. The director consequently denied reports that he had a fall out with the rest of the team.
The soundtrack of the movie was composed by Anirudh Ravichander and was released on 27 November 2015. The Telugu version was released on 11 December 2015.Nava Manmadhudu (Telugu version)
Thanga Magan's Tamil Nadu theatrical rights were sold to Sri Green Productions. The film was released on 18 December 2015. The film was dubbed and released in Telugu as Nava Manmadhudu. The satellite rights of the film were sold to Sun TV.
DNA India rated the film 3 stars and said, "Watch the movie for the fine performances by the lead actors." Filmibeat rated the film 3.0/5 and said, "Thanga Magan, though not as impressive as Velaiyilla Pattathari, manages to make you laugh and weep. It also most definitely, entertains you." OnlyKollywood rated Thanga Magan 2.75 out of 5 and added, "Thanga Magan offers rollicking fun in its simplistic, chocolate-box romance portions though its modus operandi appears plain and unequivocal in the way the familial relations are staged, especially in the second half." Behindwoods rated the film 2.5 out of 5 and wrote, "On the whole, Thanga Magan does justice to its cause, which is to entertain, but doesn't keep the audience engrossed." Tamilglitz rated the film 2.5 out of 5 and called it "a simple movie which is worth [watching]".