Synonyms: 1,3,3-trimethyl-2-[(1E,3E,5E,7E)-7-(1,3,3-trimethylindol-2-ylidene)hepta-1,3,5-trienyl]indole perchlorate;3H-Indolium, 2-(7-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-1,3,5-heptatrienyl)-1,3,3-trimethyl-, perchlorate;1,1,3,3,3,3-Hexamethylindotricarbocyanine;1,3,3-Trimethyl-2-(7-(1,3,3-trimethylindol-2-ylidene)-1,3,5-heptatrienyl)indolium perchlorate;2-(7-(1,3-Dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)hepta-1,3,5-trienyl)-1,3,3-trimethyl-3H-indolium perchlorate;NK 2421;1,3,3-Trimethyl-2-[7-(1,3,3-trimethyl-1,3-dihydro-2H-indol-2-ylidene)-1,3,5-heptatrienyl]-3H-indolium perchlorate;