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Reactions of Pt(diimine)(tdt) (tdt = 3,4-toluenedithiolate) with [M2(dppm)2(MeCN)2]²+ (M = CuΙ or AgΙ, dppm = bis(diphenylphosphino)methane) gave heterotrinuclear complexes [PtCu2(tdt)(μ-SH)(dppm)3](CIO4)(1) and [PtCu2-(diimine)a(tdt)(dppm)2](CIO4)2 (diimine = 2,2′-byridine (bpy) 2; 4,4′-dimethyl-2,2′-bipyridine (dmbpy) 3; phenanthroline (phen) 4, 5-bromophenanthroline (Brphen) 5) for M - CuΙ, but [PtAg2(tdt)(μ-SH)(dppm)3](SbF6) (6) and [PtAg2(diimine)(tdt)(dppm)2](SbF6)2 (diimine = bpy 7; dmbpy 8; phen 9; Brphen 10) for M = AgΙ. While the complexes [PtAg2(diimine)(tdt)(dppm)2](SbF6)2 (7–10) result from linkage of Pt(diimine)(tdt) and [M2(dppm)2(MeCN)2]²+ by tdt sulfur donors, formation of [PtCu2(diimine)2(tdt)(dppm)2](ClO4)2 (2–5) is related to rupture of metal-ligand bonds in the metal components and recombination between the ligands and the metal atoms by self-assembly. The formation of 1 and 6 is involved not only in dissociation and recombination of the metal components, but also in disruption of C-S bonds in the dithiolate (tdt). The dithiolate tdt adopts a chelating and bridging coordination mode in anti conformation for [PtCu2(diimine)2(tdt)(dppm)2](CIO4)2 (2–5), whereas there is the syn conformation for other complexes. Compounds 1 and 6 represent sparse examples of μ-SH-bridged heterotrinuclear PtΙΙMΙ2 complexes, in which PtΙΙ-MΙ centers are bridged by dppm and sulfur donors of tdt, whereas MΙ-MΙ (M = Cu for 1; Ag for 6) centers are linked by dppm and the μ-SH donor. The 31P NMR spectra show typical platinum satellites (JPt-P = 1450–1570 Hz) for 1–6 and Ag-P coupling for PtΙΙ-AgΙ (JAg-P = 350–450 Hz) complexes 6–10. All of the complexes show intense emission in the solid state and in frozen glasses at 77 K. The complexes [PtAg2(diimine)(tdt)(dppm)2](SbF6)2 (7–10) also afford emission in fluid acetonitrile solutions at room temperature. Solid-state emission lifetimes at room temperature are in the microsecond range. It is revealed that emission energies of the trinuclear heterometallic complexes [PtAg2(diimine)(tdt)(dppm)2](SbF6)2 (7–10) exhibit a remarkable blue shift (0.10–0.35 eV) relative to those of the precursor compounds Pt(diimine)(tdt). The crystal structures of 1, 2, 4, 6, 8, and 9 were determined by X-ray crystallography. [ABSTRACT FROM AUTHOR]