5,6-dichloro-1-ethyl-2-[2-(phenylamino)vinyl]-3-(3-sulphonatobutyl)-1H-benzimidazolium

4-[[5,6-Dichloro-1-ethyl-2-[2-(phenylamino)ethenyl]-1H-benzimidazol-3-ium]-3-yl]-2-butanesulfonate