1 6FE 4-[[4-(dimethylamino)cyclohexa-2,5-dien-1-ylidene]-(4-methoxyphenyl)methyl]-N,N-dimethyl-aniline 1.000 2 CVI Crystal violet 0.833 3 MGR Malachite green 0.733 4 1OM 4-{bis[4-(dimethylamino)phenyl]methyl}phenol 0.710