The reaction of cis-(C6H5CN)2PtCl2 and Na2PtCl4 with the dienes 1,4-pentadiene and 2,5-diphenyl-1,5-hexadiene yields the species cis-(1,4-pentadiene) PtCl2 and cis-(2,5-diphenyl-1,5-hexadiene)PtCl2, respectively. The compounds have been fully characterized by elemental analysis, IR, 1H-NMR, mass spectroscopy and by X-ray methods