The title compounds were synthesized by the reactions of [NH 4 ] 2 [MS 4 ] (M=Mo, W), AgI and Hmimt in acetone and characterized by IR, 1 H NMR and UV–Vis spectroscopy. The polymeric structure of [WS 4 Ag 2 (Hmimt) 2 ] n was determined by X-ray crystallography. In this compound, there are two distinctly different coordination modes for the silver atoms. One Ag atom has a pseudo-tetrahedral geometry with one terminal monodentate-S Hmimt, two μ 2 -S bridging Hmimt and one S atom of a monodentate WS 4 unit. The other is surrounded by four sulfur atoms belonging in pairs to two WS 4 fragments; the coordination geometry is distorted tetrahedral. The [WS 4 Ag 2 (Hmimt) 2 ] n polymer represents the first example of tetrathiometalate anions [MS 4 ] 2− (M=Mo, W, or V) coordinated to another metal atom in a monodentate fashion. In both crystal structures determined the Hmimt ligands are present in the thione form, with coordination taking place via the sulfur atom only.