The molecule is an amino sulfonic acid that is 4-[(4-methylenecyclohexa-2,5-dien-1-ylidene)amino]benzenesulfonic acid in which the hydrogens of the methylene group are replaced by 4-amino-3-methyl-5-sulfophenyl and 4-[(4-sulfophenyl)amino]phenyl groups. The disodium salt is the biological stain C.I. Acid Blue 22, also known as water blue. It is an organosulfonic acid, a ketimine and an amino sulfonic acid. It is a conjugate acid of a NSC 56820(2-).
2-amino-3-methyl-5-[[4-(4-sulfoanilino)phenyl]-[4-(4-sulfophenyl)iminocyclohexa-2,5-dien-1-ylidene]methyl]benzenesulfonic acid