Acenaphthylene is a polycyclic aromatic hydrocarbon. The molecule resembles naphthalene with positions 1 and 8 connected by a C2H2 unit. It is a yellow solid. Unlike many polycyclic aromatic hydrocarbons, it has no fluorescence.
Acenaphthylene occurs as about 2% of coal tar. It is produced industrially by dehydrogenation of acenaphthene. More than 20% of the carbon in the universe may be associated with PAHs.
Hydrogenation gives the more saturated compound acenaphthene.
It functions as a ligand for some organometallic compounds.