The molecule is an organosulfonate oxoanion obtained by deprotonation of the sulfo groups of 4-[(7-phenyl-3-sulfobenzo[a]phenazin-5-ylidene)amino]benzene-1,3-disulfonic acid. It is a conjugate base of an azocarmine B free acid.
4-[(7-phenyl-3-sulfonatobenzo[a]phenazin-7-ium-5-yl)amino]benzene-1,3-disulfonate