A method of preparing bis(cis,cis-cyclo-octa-1,5 diene) platinum and palladium by reducing [Pt Cl.sub.2 (1,5-C.sub.8 H.sub.12)] or [Pd Cl.sub.2 (1,5-C.sub.8 H.sub.12)] in the presence of a solvent not having an active hydrogen atom, methods of preparing various other platinum and palladium compounds, some of which are novel from bis(cis,cis-cyclo-octa-1,5 diene) platinum and palladium, and methods of depositing films of platinum or palladium metal on a substrate by coating the substrate with various platinum or palladium compounds which are then decomposed.