Treatment of [Et4N](2)[(edt)(2)Mo2S2(mu-S)(2)] (1) (edt = ethanedithiolate) with equimolar CuBr afforded an anionic hexanuclear cluster [Et4N](2)[(edt)(2)Mo-2(mu-S)(3)(mu(3)-S)Cu](2)center dot 2CH(2)Cl(2). On the other hand, reactions of 1 with 2 equiv of CuBr in the presence of 1,2-bis(diphenylphosphino) methane (dppm) and pyridine (Py) ligands gave rise to two neutral tetranuclear clusters [(edt)(2)Mo2O2(mu-S)(2)Cu-2(dppm)(2)] (3) and [(edt)(2)Mo2O(mu(3)-S)(mu-S)(2)Cu-2(Py)(4)] (4), respectively. The reaction of 1 with 2 equiv of CuBr followed by the addition of a mixture of dppm and Py (molar ratio = 1:2) yielded another neutral tetranuclear cluster [(edt)(2)Mo-2(mu-S)(2)(mu(3)-S)(2)Cu-2(dppm)(Py)]center dot Py (5 center dot Py). Compounds 2-5 have been characterized by elemental analysis, UV-vis spectra, IR spectra, H-1 NMR, and X-ray analysis. The structure of the dianion of 2 can be viewed as having a [Mo4S8Cu2] core in which two chemically equivalent [Mo-2(mu-S)(3)(mu(3)-S)(edt)(2)Cu](-) anions are linked by two extra Cu-S-edt bonds. The molecular structure of 3 may be visualized as being built of one [(edt)(2)Mo2X2(mu-S)(2)](2-) dianion and one [Cu-2(dppm)(2)](2+) dication that are connected by a pair of M-mu-S-edt bonds. Compound 4 is formed by the affiliation of two Cu(I) atoms only at one end of the [(edt)(2)Mo2S2(mu-S)(2)] moiety, connecting with the S-t atoms and the S-edt atom. Cluster 5 center dot Py can be viewed as being constructed from the addition of one Cu atom onto the incomplete cubanelike [Mo2S4Cu] framework through one terminal sulfur and one edt sulfur. Among the four clusters, 3 and 4 have internal mirror symmetry or pseudo mirror symmetry, respectively, while 2 and 5 are asymmetric clusters with racemic formation.