The alkynylation of trans-[Pt(C6F5)2(tht)2] (tht = tetrahydrothiophene) with LiC⋮CR in diethyl ether (R = Ph, SiMe3) or THF (R = tBu) leads to novel dianionic species [trans-Pt(C6F5)2(C⋮CR)2]2- (R = Ph (1), SiMe3 (2), tBu (3)) which have been isolated as tetrabutylammonium salts. Treatment of (NBu4)2[trans-Pt(C6F5)2(C⋮CR)2] (R = Ph, SiMe3, tBu) with 2 equiv of cationic hydride reagents of the type [trans-PtHL2(acetone)]+ (L = PPh3, PEt3) in acetone form, via a ligand replacement, simple bis(η2-alkyne) trinuclear zwitterionic complexes trans,trans,trans-{[Pt(C6F5)2(μ-η1:η2-C⋮CR)2](PtHL2)2} (R = Ph, L = PPh3 (4a), PEt3 (4b); R = SiMe3, L = PPh3 (5a), PEt3 (5b); R = tBu, L = PEt3 (6b)). The structure of complex 4b has been determined by X-ray diffraction methods.