A bis-cyclometallating ligand bearing two different terdentate coordination sites (N---C---N: dipyridyI-benzene; P---C---P: diphosphaalkenebenzene moieties) has been synthesised. Selective reactions of appropriate metal complex precursors afforded a heterodinuclear ruthenium(II)-palladium(II) complex characterised by 1H, 13P NMR spectroscopy and FAB-MS techniques. We have compared its electrochemical and spectroscopic properties (absorption and emission) with the individual ruthenium(II) and palladium(II) subunits.