The molecule is a bis(azo) compound that is naphthalene-2,7-disulfonic acid in which the hydrogens at positions 3, 4, 5, and 6 are replaced by (p-nitrophenyl)azo, amino, hydroxy, and (p-sulfophenyl)azo groups, respectively. The trisodium salt is the histological dye 'naphthalene blue black CS'. It has a role as a fluorochrome and a histological dye. It is a C-nitro compound, an aminonaphthalenesulfonic acid, a bis(azo) compound, a member of naphthols and a member of azobenzenes. It is a conjugate acid of a 4-amino-5-hydroxy-3-[(4-nitrophenyl)diazenyl]-6-[(4-sulfonatophenyl)diazenyl]naphthalene-2,7-disulfonate.
4-amino-5-hydroxy-3-[(4-nitrophenyl)diazenyl]-6-[(4-sulfophenyl)diazenyl]naphthalene-2,7-disulfonic acid