A series of dinuclear platinum(II) terpyridyl and terpyridyl-crown complexes with 2,2-dicyano-1,1-ethylenedithiolate (i-mnt), 1,3-benzenedithiolate (SC₆H₄S-1,3) and N,N-diethyldithiocarbamate (dtc) bridging ligands have been synthesized and characterized. Their photophysical and electrochemical properties, together with that of the related mononuclear platinum(II) terpyridyl-crown complex and its crown-free analogue, have been studied. The ion-binding properties of the terpyridyl-crown complexes have been determined by electronic absorption spectroscopy and ESI-mass spectrometry. The X-ray crystal structures of [Pt(trpyCC-benzo-15-crown-5)Cl]PF₆, [{Pt(trpy)}₂(μ-SC₆H₄S-1,3)](PF₆)₂ and [{Pt(trpy)}₂{μ-(i-mnt)}](PF₆)₂ have also been determined.