For the first time a study has been made of the effect of copper and nickel complexes containing nitrogen and sulphur atoms in the chelate unit on the processes of oxidation of styrene and cumene. The catalytic activity of these metal complexes supported by silica gel has also been investigated. The complexes exhibit catalytic activity in the oxidation of cumene and styrene. Nickel complexes are active in the oxidation of styrene, whereas copper complexes inhibit the oxidation of styrene. On the other hand, the oxidation of cumene is catalysed by copper complexes and inhibited appreciably by nickel complexes. In the oxidation of styrene, heterogenization of copper complexes leads to change in the inhibiting function to a catalytic function.