The molecule is a hydrochloride that is the dihydrochloride of 4,4'-[1,3-phenylenebis(diazene-2,1-diyl)]di(benzene-1,3-diamine). Bismarck brown Y is a metachromatic dye which stains acid mucins yellow. It is also a constituent of Papanicolaou's EA solutions, used for cervical, and other smears. It has a role as a histological dye, a fluorochrome and an allergen. It contains a basic brown 1.
4-[[3-[(2,4-diaminophenyl)diazenyl]phenyl]diazenyl]benzene-1,3-diamine;dihydrochloride