The three-solvent reaction of (Bu(4)N)(2)[Zn(dmt)(2)] (dmt = C3S52- = 3-thioxo-1,2-dithiole-4,5-dithiolato) (CH2-Cl2), (Et(4)N)(2)tto (tto = C2S42- = tetrathiooxalate) (H2O), and CuCl2 . 2H(2)O (CH3OH) yields the anionic tetrameric copper complex (Bu(4)N)(2)[Cu(dmt)](4). The dianion contains a planar, eight-membered ring core of four Cu atoms and four S atoms. The dmt ligand coordinates for the first time in this particular fashion.