The molecule is an organic heterotetracyclic compound that is 7-phenyl-5-imino-5,7-dihydrobenzo[a]phenazine-3-sulfonic acid in which the imino hydrogen is replaced by a 2,4-disulfophenyl group. The disodium salt is the biological stain 'azocarmine B'. It is an arenesulfonic acid, an imine and an organic heterotetracyclic compound. It is a conjugate acid of an azocarmine B(2-).
4-[(7-phenyl-3-sulfobenzo[a]phenazin-5-ylidene)amino]benzene-1,3-disulfonic acid