The rhodium(III) complex mercis-[RhCl3(PPh(2)py-P,N(PPh(2)py-P)] (1) (PPh(2)py = diphenyl (2-pyridyl)phosphine) has been prepared from RhCl(3)(.)3H(2)O and PPh(2)py and converted to the trans, cis-[RhCl2(PPh(2)py-P,N)(2)]PF6 (2) in acetone solution by treatment with Ag+ and PF6-. Ruthenium(III) and ruthenium(II) compounds with PPh(2)py, mercis[RuCl3(PPh(2)py-P,M(PPh(2)py-P)] (3) and mer-[RuCI(PPh2PY-PM2(PPh2PY- P)ICI (5) have been obtained from DMSO precursor complexes. In a chloroform solution, complex (5) isomerizes to fac-[RuCl(PPh(2)py-P,N-2(PPh(2)py-P)]Cl (fac-5). All compounds have been characterized by MS, UV-vis, IR, and H-1 and P-31{H-1} NMR spectroscopy, and the Ru(III) compound has been characterized by EPR spectroscopy as well. The crystal structures of 1, 2, 3, and fac-5 have been determined. In all compounds under investigation, at least one pyridylphosphine acts as a chelate ligand, The 31P chemical shifts for chelating PPh(2)py-P,N depend on the Ru-P bond lengths.