The bidentate ligand benzoyl(2-pyridyl)thiourea (L1) was prepared by reaction of benzoyl isothiocyanate with primary amine (2aminopyridine) but the reaction with secondary amine bis(2pyridyl)amine, yielded the unexpected product bis(2-pyridyl)benzoylamine (L2). Mononuclear complexes of the general formula [(η 6arene)Ru(L)Cl] + {where, L = L1, arene = benzene (1); p-cymene (2); L = L2, arene = benzene (5); p-cymene (6)} and [Cp*M(L)Cl] + {where, L = L1, M = Rh (3), Ir (4); L = L2, M = Rh (7), Ir (8)}, 715 respectively, were formed by reaction of the ligands L1 and L2 with precursor complexes [(η 6 -arene)Ru(μ-Cl)Cl] 2 and [Cp*M(μ-Cl)Cl] 2 (M = Rh, Ir). The cationic complexes were characterized by FT-IR, UV/Vis, and 1 H-NMR spectroscopy as well as mass spectrometry. Xray crystallographic studies of these complexes reveal piano-stool-like arrangements around the metal atoms with six-membered metallacycles in which L1 and L2 act as a N,S-and N,N' chelating ligands, respectively.fields and their metal complexes have been utilized for several decades and are widely employed in coordination chemistry, supramolecular chemistry and materials synthesis. [20][21][22][23][24][25] To the best of our knowledge there is no report available in the literature regarding reactions of arene ruthenium and Cp*Rh and Cp*Ir complexes with benzoyl-(2-pyridyl)thiourea/ bis(2-pyridyl)benzoylamine ligands. Herein, the syntheses of a series of new mononuclear half-sandwich complexes of arene Ru II , Cp*Rh III and Cp*Ir III with these bidentate ligands are reported. The ligands used in this study are shown in Scheme 1. Scheme 1. Ligands used in this study.