Synonyms: 1H-Benzimidazolium,5-cyano-2-[3-[5-cyano-1-ethyl-1,3-dihydro-3-(3-sulfopropyl)-2H-benzimidazol-2-ylidene]-1-propenyl]-1-ethyl-3-(3-sulfopropyl)-,inner salt, sodium salt (9CI); Benzimidazolium,6-cyano-2-[3-[5-cyano-1-ethyl-3-(3-sulfopropyl)-2-benzimidazolinylidene]propenyl]-3-ethyl-1-(3-sulfopropyl)-,hydroxide, inner salt, sodium salt (8CI)