A cyclotriphosphazene ligand containing the spirocyclic 2,2'-dioxybiphenyl group and 2-methy1-3-pyridyloxy moieties was synthesized. A Ru(11) complex was prepared from the reaction of [RuCl2(p-cymene)](2) with this ligand. The structures of the ligand and the Ru(II) complex were characterized by FT-IR, H-1 and P-31 NMR spectroscopy. In addition, the molecular structure of the ligand was confirmed by X-ray crystallography. The Ru(II) complex was used as catalyst for the Catalytic Transfer Hydrogenation (CTH) of p-substituent acetophenone derivatives in the presence of KOH. The antimicrobial activities of the ligand and the complex have also been studied. The antimicrobial activities have been screened in vitro against Gram-positive (Staphylococcus aureus ATCC 6538, Bacillus cereus ATCC 7064, Listeria monocytogenes ATCC 15313, Micrococcus luteus La 2971) and Gram-negative (Escherichia coil ATCC 11230, Klebsiella pneumoniae UC57, Pseudomonas aeruginosa ATCC 27853, Proteus vulgaris ATCC 8427, Enterobacter aerogenes ATCC 13048) bacteria and yeast cultures (Candida albi cans ATCC 10231, Kluyveromyces fragills NRRL 2415, Rhodotorula rubra DSM 70403) using both the disk diffusion and dilution methods. (C) 2015 Elsevier Ltd. All rights reserved.