N-(4''-(Dimethylamino)-5'-(4-(dimethylamino)phenyl)-[1,1':3',1''-terphenyl]-4-yl)-N-methyl-4-(methylamino)benzamide is an impuriy of α,α-Bis[4-(dimethylamino)phenyl]-4-(methylamino)-benzenemethanol which is a product from degradation of methyl green.