Tetradentate Schiff base ligands, derived from aromatic aldehydes and aliphatic diamine (2,2'-dimethylpropandiamine), and their vanadyl complexes have been prepared and characterized. Catalytic potential of these complexes was tested for the oxidation of cyclooctene and styrene using tert-butylhydroperoxide (TBHP) as oxidant. The effects of molar ratio of oxidant to substrate, temperature and solvent have been studied. Excellent selectivity of epoxidation for cyclooctene and good selectivity for styrene were obtained. The mechanism of oxidation has also been discussed. (C) 2008 Elsevier B.V. All rights reserved.