The complexes PtR 2(diene) (R = C 6F 5 or p-HC 6F 4; diene = cis, cis-cycloocta-1,5-diene (cod), dicyclopentadiene (dcy), norbornadiene (nbd) or hexa-1,5-diene (hex)) have been prepared by the organolithium route. Reaction of PtCl 2(cod) with an equimolar amount of TlO 2CR (R = C 6F 5 or p-HC 6F 4) in pyridine yields Pt(R)Cl(cod), which have been converted into Pt(R)X(cod) (X = Br or I) by halogen exchange reactions. Other decarboxylations result in diene displacement giving cis-Pt(C 6F 5)Cl(py) 2 and cis- and trans-Pt(C 6F 5) 2(py) 2. The complexes, cis-Pt(C 6F 5) 2L 2 (L = py or Ph 3P) and cis-Pt( p-HC 6F 4) 2(PPh 3) 2) are formed by ligand replacement reactions of PtR 2(cod), but Pt(C 6F 5) 2(cod) does not react with N, N, N′, N′-tetramethylethylenediamine (tmed) nor Pt(C 6F 5) 2(nbd or dcy) with ethylenediamine (en). Diene displacement occurs more readily from PtR 2(hex) giving Pt(C 6F 5) 2L 2 (L 2 = cis-(NH 3) 2, en, tmed or 1,10-phenanthroline) and cis-Pt( p-HC 6F 4) 2(PPh 3) 2.