The complexes PtR2(diene) (R = C6F5 or p-HC6F4; 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 PtCl2(cod) with an equimolar amount of TlO2CR (R = C6F5 or p-HC6F4) 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(C6F5)Cl(py)2 and cis- and trans-Pt(C6F5)2(py)2. The complexes, cis-Pt(C6F5)2L2 (L = py or Ph3P) and cis-Pt(p-HC6F4)2(PPh3)2) are formed by ligand replacement reactions of PtR2(cod), but Pt(C6F5)2(cod) does not react with N,N,N′,N′-tetramethylethylenediamine (tmed) nor Pt(C6F5)2(nbd or dcy) with ethylenediamine (en). Diene displacement occurs more readily from PtR2(hex) giving Pt(C6F5)2L2 (L2 = cis-(NH3)2, en, tmed or 1,10-phenanthroline) and cis-Pt(p-HC6F4)2(PPh3)2.