The molecule is an arenesulfonic acid that is m-[(4-sulfophenyl)diazenyl]benzene-1-sulfonic acid carrying a (2-hydroxynaphthalen-1-yl)diazenyl substituent at position 2. The disodium salt is the biological stain 'Biebrich scarlet'. It has a role as a histological dye. It is a member of naphthols, a bis(azo) compound, a member of azobenzenes and an arenesulfonic acid. It is a conjugate acid of a Biebrich scarlet(2-).
2-[(2-hydroxynaphthalen-1-yl)diazenyl]-5-[(4-sulfophenyl)diazenyl]benzenesulfonic acid