2-[2-[(3-ethyl-5-methoxybenzothiazol-2(3H)-ylidene)methyl]but-1-enyl]-5-methoxy-3-(3-sulphonatopropyl)benzothiazolium

2-[2-[(3-Ethyl-5-methoxybenzothiazol-2(3H)-ylidene)methyl]-1-butenyl]-5-methoxy-3-(3-sulfonatopropyl)benzothiazol-3-ium