Bimetallic zwitterionic platinum(II)-rhodium(I) complexes of the type [(C6F5)(3)Pt(mu-PPynPh3-n)Rh(CO)(2))] and [(C6F5)(3)Pt(mu-PPynPh3-n)Rh(diene))] (n = 2, 3; Py = 2-pyridyl) have been prepared. The P end of the bridging ligands (mu-PPynPh3-n) is always coordinated to the Pt center, while the N-donor ends chelate the Rh atom, giving metallacycles comparable to pyrazolylborate-Rh complexes. These metallacycles can adopt two conformations, either with the Pt complex in pseudoaxial position approaching the Rh center or with the Pt complex in a remote position. The preferred conformation depends on the steric hindrance at the rhodium center. In less sterically demanding Rh-carbonyl complexes the Pt moiety gets close to the Rh moiety as this brings closer the opposite charges of the zwitterion. For diene complexes mixtures of conformers are obtained. The X-ray structures of [(C6F5)(3)Pt(mu-PPhPy2)Rh(COD)] (COD = 1,5-cyclooctadiene) and [(C6F5)(3)Pt(mu-PPhPy2)Rh(CO)(2)] are reported.