Irradiation of 1-p-substitutedphenyl-4-phenyl-1,3-butadienes gave mixtures of 1-p-substituted-phenylnaphthalenes and 7-substituted-1-phenylnaphthalenes. Photocyclization of 1-m-substituted-phenyl-4-phenyl-1,3-butadienes gave 1-m-substitutedphenylnaphthalenes, 6-substituted-1-phenylnaphthalenes, and 8-substituted-1-phenylnaphthalenes. Characterization of the photoproducts was achieved through synthesis by an independent method.