3-(1-Ethyl-2-methylindol-3-yl)-3-(2-methyl-4-diethylaminophenyl)-4-azaphthalide;3-(4-Diethylamino-2-methylphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide;3-(4-Diethylamino-2-methylphenyl)-3-(1-ethyl-2-methylindole-3-yl)-4-azaphthalide;3-(4-Diethylamino-2-methylphenyl)-3-(2-methyl-1-ethylindol-3-yl)-4-azaphthalide;Yamamoto Blue 220