The immobilization of molybdenum (Mo) compounds on poly(4-vinylpyridine) (P4VP) microspheres for catalytic epoxidation was reported. P4VP-supported Me compounds were highly efficient and selective for the epoxidation of cis-cyclooctene using hydrogen peroxide (H2O2) as oxygen source. When ethanol was used as solvents, outstanding catalytic activity and selectivity were observed for Mo-containing catalysts in the epoxidation of cis-cyclooctene. A completely green epoxidation system based on H2O2 and cleaner solvent has been achieved, and the heterogenized Mo catalyst can be recovered for five times without loss of its activity. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 558-562, 2010