The title compound, (C(4)H(12)N)(3)[CuMo(2)S(8)]·C(3)H(7)NO, was obtained from the self-assembly of tetra-thio-molybdate, tetra-methyl-ammonium nitrate and cuprous sulfide in dimethyl-formamide (DMF). The asymmetric unit contains three (NMe(4))(+) cations, one [Mo(2)S(8)Cu](3-) anion and one DMF solvent mol-ecule, and no obvious inter-actions are observed between these species. The trinuclear anion can be viewed as fused [MoS(4)Cu](-) units sharing a copper center. The geometric parameters of the trivalent anion are comparable to those reported for other related salts including isomorphous anions, namely (NEt(4))(2)(PPh(4))[Mo(2)S(8)Cu] (a) and (Ph(3)P=N=PPh(3))(2)(NEt(4))[W(2)S(8)Cu]·2CH(3)CN (b). However, the Mo-Cu-Mo angle is found to be 160.24 (3)° for the title salt, while this angle is 162.97 (2)° in (a) and the W-Cu-W angle is 170.3 (2)° in (b), indicating that the largest deviation from linearity is in the title compound.