The imidazole-tagged BINAP ligands were synthesized and used for Ru-catalyzed asymmetric hydrogenation of beta-keto esters in ionic liquid (IL) systems. The Ru-BINAP catalysts with the imidazolium tags show high catalytic activity and enantioselectivity, which closely parallel the performance of unmodified BINAP. The catalyst recycling experiments using [bmim]Tf2N/MeOH system demonstrated that introducing imidazolium moieties to the BINAP backbone can effectively enhance the affinity of the Ru-catalysts to the IL, reduce Ru leaching and improve catalysts stability, and after several cycles no significant loss of activity and enantioselectivity was observed. (C) 2013 Elsevier B.V. All rights reserved.