Novel chiral dimeric salen-Mn complexes were synthesized and their catalytic effects in asymmetric epoxidation of non-functionalized alkenes were investigated. The study was undertaken using a dimeric catalyst to establish whether high enantioselectivity could be achieved just like its active monomer, and whether the bigger complex could be efficiently recovered and reused by a simple controlling solvent system. The result showed that high activity and enantioselectivity were achieved. The dimeric complex formation enhanced the catalyst's reactivity and stability without compromising its enantioselectivity. Catalyst 3a, unlike its monomer, could be easily recovered and reused for several cycles under the mild reaction conditions before a marked decline in yield and ee was observed. (C) 2003 Elsevier B.V. All rights reserved.