The molecule is an organosulfonate oxoanion obtained by the removal of two protons from N-ethyl-4-[(4-{ethyl[(3-sulfophenyl)methyl]amino}phenyl)(4-sulfophenyl)methylidene]-N-[(3-sulfophenyl)methyl]cyclohexa-2,5-dien-1-iminium (the free acid form of the biological stain 'acid green 5'). It is a conjugate base of an acid green 5(1+).
3-[[N-ethyl-4-[[4-[ethyl-[(3-sulfonatophenyl)methyl]azaniumylidene]cyclohexa-2,5-dien-1-ylidene]-(4-sulfonatophenyl)methyl]anilino]methyl]benzenesulfonate