Photochemical reactions of 1-o-nitrophenyl-4-phenyl-1, 3-butadiene, 1, 4-di-o-nitrophenyl-1, 3-butadiene, 1-o-nitrophenyl-6-phenyl-1, 3, 5-hexatriene, and 1, 6-di-o-nitrophenyl-1, 3, 5- hexatriene all gave the appropriate 2-substituted isatogen. The related m-and p-nitrophenyl