The synthesis, structural characterization of cationic 2-(2-pyridyl)benzoazole)ruthenium(II) complexes and their applications in biphasic hydrogenations of alkenes is reported. Reactions of 2-(2-pyridyl)benzoimidazole (L1), 2-(2-pyridyl)benzothiazole (L2) and 2-(2-pyridyl)benzoxazole (L3) with [eta(6)-(2-phenoxyethanol)RuCl2](2) produced the corresponding cationic complexes [eta(6)-(2-phenoxyethanol)RuCl(L1)]Cl (1), [eta(6)-(2-phenoxyethanol)RuCl(L2)]Cl (2) and [eta(6)-(2-phenoxyethanol)RuCl(L3)]Cl (3) in good yields. Solid state structures of 1-3 confirmed the bidentate coordination modes of L1-L3 and formation of cationic species through displacement of one chloride ligand from Ru(II) coordination sphere. Complexes 1-3 produced active catalysts for high pressure hydrogenation of alkenes both in methanol and biphasic conditions. Relatively lower activities were observed in the hydrogenation of terminal alkynes giving a mixture of alkane and alkene products. Complexes 1-3 were recyclable under biphasic conditions and retained significant catalytic activities in six cycles. Reaction parameters such as substrate/catalyst ratio, temperature, and aqueous/organic ratio affected the catalytic trends. (C) 2014 Elsevier B.V. All rights reserved.