The photochemical reaction of 1-cyanonaphthalene (1-CNNap) with substituted pyridine was studied. Irradiation of a benzene solution of 1-CNNap (0.02 M) in the presence of 3-cyano-2-methoxypyridine (0.02 M) gave a 1:1 adduct in 24% yield and the pyridine dimer in 56% yield, when the reaction conversion reached 32%. Photoaddition of 1-CNNap with 3-cyano-2-methoxy-6-methylpyridine, 3-cyano-4,6-dimeth