2,5-Cyclohexadien-1-imine, 4-(4-imino-2,5-cyclohexadien-1-ylidene)- 4-(4-Imino-2,5-cyclohexadien-1-ylidene)-2,5-cyclohexadien-1-imine 6050-16-4 Benzidine-4,4'-diimine Benzidinediimine