Synonyms: 3H-INDOLIUM, 2-[3-CYANO-5-(1,3-DIHYDRO-1,3,3-TRIMETHYL-2H-INDOL-2-YLIDENE)-1,3-PENTADIENYL]-1,3,3-TRIMETHYL-, PERCHLORATE;2-[(1E,3Z)-3-CYANO-5-(1,3,3-TRIMETHYL-1,3-DIHYDRO-2H-INDOL-2-YLIDENE)-1,3-PENTADIENYL]-1,3,3-TRIMETHYL-3H-INDOLIUM PERCHLORATE