A series ligands (L3-14) of derived from 2-(2'-quinolyl)benzimidazole (QuBim, L-1) and 2-(2'-quinolyl)-5,6-dimethylbenzimidazole (QuDmBim, L-2) which are an NN-type ligands have been synthesized and characterized with various techniques such as NMR, UV-vis, FT-IR spectroscopy, elemental analysis and X-ray diffraction. The substituted ligands derived from QuBim and QuDmBim have been used as sustaining ligands in the Ru-II-catalyzed transfer hydrogenation (TH) of acetophenone to secondary alcohols in the presence i-PrOH/KOH. The half-sandwich complexes (C1-14) of Ru-II with NN-type ligands have been synthesized by cleavage of [(eta(6)-p-cymene)Ru(mu-Cl)](2) dimer. The resulting complexes have been characterized by NMR, UV-vis, FT-IR spectroscopy and elemental analysis. The thermal and electrochemical properties of selected complexes and ligands were investigated. (C) 2020 Elsevier B.V. All rights reserved.