The synthesis of highly active ruthenium(II) catalyst based on N-heterocyclic carbene (NHC) bearing alkyl and aryl groups is reported. The complexes are easily handled in very good yields via synthesis of silver -NHC complexes and subsequent reaction with [RuCl2(p-cymene)](2) in dichloromethane (DCM) under N-2 condition. All new compounds were characterized by LC-MSMS, elemental analysis, NMR spectroscopy and X-ray diffraction. With the development of a more efficient catalytic system for transfer hydrogenation of aryl ketones and aldehydes in mind, the catalytic performance of the Ru-NHC complexes for transfer hydrogenation was investigated. (c) 2015 Elsevier B.V. All rights reserved.