Synonyms: 1H,5H-[1]Benzopyrano[6,7,8-ij]quinolizinium,11-(1,1-dimethylethyl)-9-[3-[1-[6-[(2,5-dioxo-1-pyrrolidinyl)oxy]-6-oxohexyl]-1,3-dihydro-3,3-dimethyl-5-sulfo-2H-indol-2-ylidene]-1-propenyl]-2,3,6,7-tetrahydro-,inner salt (9CI); DY 635; DY 635 NHS Ester