Abstract: 1, I-Di-p-cyanophenyl-3, 3-dimethyl-5, 5-diphenyl-l, 4-pentadiene and 1, 1, 5, 5- tetra-p-cyanophenyl-3, 3-dimethyl-1, 4-pentadiene were synthesized for comparison of their photochemistry with the parent diene, 1, 1, 5, 5-tetraphenyl-3, 3-di-methyl-1, 4-pentadiene, ...