produced. In photoamination with t-butylamine in acetonitrile, 3a and 3b were mainly formed as a consequence of the incorporation of acetonitrile to 1a and 1b. The photoamination of 1-phenyl-3,4-dihydronaphthalene (1c) with isopropylamine or t-butylamine gave cis- and trans-N-substituted 1-phenyl-2-amino-1,2,3,4-tetrahydronaphthalenes (15 and 16) in a ratio of ca. 8:2. The mechanism of photoamination is discussed