The solution and gas-phase photophysical and photochemical properties of a series of bicyclic and alicyclic thioketones (apothiocamphor (1), thiocamphor (2), thiofenchone (3), endo-5,6-trimethylene-2-norborneanthione (4), 3,3-diethylbicyclo[3.2.1]octane-2-thione (5), 2,2-diethyl-5,5-dimethylcyclopentanethione (6), 2-ethyl-2,6,6-trimethylcyclohexanethione (7), and 2,4,4-trimethyl-3-hexanethione (8)) are reported. Photolysis in solution typically gives rise to products arising from insertion into beta, gamma, and, in one case (4), delta carbons to form cyclic thiols. This chemistry is analogous to that observed in earlier studies. Novel photochemistry is found in the gas phase where Norrish type II products are also isolated from several substrates (1, 2, 5, 6, and 7). The effect of the quencher gas, butane, on both the spectral and photochemical properties of 2 in the gas phase provide evidence to support the proposal that che Norrish type II chemistry arises from initially populated vibrationally excited levels of S-2.