New allylic complexes of ruthenium(II) of the type [Ru(all)2(diolefin)](all = allyl or 2-methylallyl; diolefin cyclo-octa-1,5-diene or norbornadiene) are described. The allylic ligands in these complexes are asymmetrically bonded. The complexes react with allyl halides to give halogeno-bridged complexes of the type [Ru2X2(all)2(diolefin)2](X = Cl or Br). On treatment with triphenylphosphine cyclo-octa-1,5-diene is displaced from [Ru(2-methylallyl)2C8H12] giving [Ru(2-methylallyl)2(PPh3)2]. This in turn reacts with carbon monoxide to give [Ru(CO)3(PPh3)2] and 2,5-dimethylhexa-1,5-diene. Nuclear magnetic resonance and far-infrared data are given.