The molecule is an arenesulfonic acid that is 3-hydroxynaphthalene-2,7-disulfonic acid carrying a {2-sulfo-4-[(4-sulfophenyl)diazenyl]phenyl}diazenyl group at position 4. The tetrasodium salt is the biological stain 'Ponceau S'. It has a role as a histological dye and a fluorochrome. It is an arenesulfonic acid, a member of azobenzenes, a bis(azo) compound and a member of naphthols. It is a conjugate acid of a Ponceau S(4-).
3-hydroxy-4-[[2-sulfo-4-[(4-sulfophenyl)diazenyl]phenyl]diazenyl]naphthalene-2,7-disulfonic acid