4,4′ Diamino 2,2′ stilbenedisulfonic acid

4,4′-Diamino-2,2′-stilbenedisulfonic acid is the organic compound with the formula (H₂NC₆H₃SO₃H)₂C₂H₂. It is a white, water-soluble solid. Structurally, it is a derivative of trans-stilbene, containing amino and sulfonic acid functional groups on each of the two phenyl rings.

The compound is a popular optical brightener for use in laundry detergents.

It is produced by reduction of 4,4′-dinitro-2,2′-stilbenedisulfonic acid with iron powder.