Reactions between [Pt(C CR)(4)](2-) (R=Tol a, C6H4OMe-4 b, C6H4OMe-3 c) and Cd2+ depend on the media and the alkynyl substituent, leading to the formation of yellow tetranuclear solvate complexes [Pt(C CR)(4)Cd(acetone)](2) la, b(acetone)(2) and [Pt(C CC6H4OMe-3)(4)Cd(dmso)](2) 1c(dmso)(2) or white polymeric solvate-free species [Pt(C CR)(4)Cd](x) 1'a-c Treatment of 1a,b(acetone)(2) or 1'a-c with N-donor ligands affords a series of tetranuclear clusters [Pt(C CR)(4)CdL](2) (L=py; 2a-c. R=Tol; L=NC5H4CH3-4 3, NC5H4CF3-4 4, pzH 5). X-ray crystallographic studies reveal that, in the tolyl complexes (2a, 4, and 5), the Cd-L2+ unit is closely bonded to one Pt -C-alpha(acetylide) bond (Pt-Cd = 2 7, Cd-C-alpha similar to 2.48 angstrom), and the resulting "Pt(C CTol)(4)CdL" unit dimerizes by two additional eta(2)-Cd-acetylide and a weaker Pt center dot center dot center dot Cd bonding interaction leading to a planar unsymmetrical rhomboidal metal core. By contrast, the m-methoxyphenyl derivatives (2c, 1c(dmso)(2)) form symmetncal Pt2Cd2 cores, with each Cd bonded (coordination number, C.N.=5) to the incoming ligand (pyridine 2c, dmso 1c(dmso)(2)) and four Pt-C-alpha bonds (Pt-Cd 2 85; Cd-C-alpha 2 470(10)-2 551(5) angstrom) of different Pt-II fragments. Evidence of ligand dissociation was found for the solvate (1 a,b(acetone)(2), 1c(dmso)(2)) and NC5H4CF3-4 (4) derivatives by NMR and UV-vis absorption spectra. All tetranuclear aggregates exhibit bright blue to green luminescence in the solid state. Time-dependent density functional theory (TD-DFT) calculations were performed to shed light on the nature of the electronic transitions In the solvate la,b(acetone)2 and 1c(dmso)2, emissions have been assigned to a platinum-alkynyl to cadmium charge transfer ((MLM)-M-3'CT), mixed with some intraligand 3IL(C CR) character. In the imine derivatives 2-5, they are suggested to come from an excited state of large Pt(d)/pi C CR ->pi*(imine) MLL'CT character, mixed with some Pt(d)/pi(C CR)-> Pt2Cd2/pi*C CR (ML'M'CT) contribution.