Rare examples of (mu-eta(2):eta(2) -disulfido)dicopper complexes have been prepared from Cu(I) and Cu(II) complexes of beta-diketiminate and anilido-imine supporting ligands. A novel byproduct derived from sulfur functionalization of the methine position of a beta-diketiminate ligand was identified. DFT calculations on [(LCu)(2)X-2] (L = beta-diketiminate, X = 0 or S) complexes rationalize the absence of a bis(mu-sulfido)dicopper isomer, [Cu-2(mu-S)(2)](2+), in the synthetic reactions, yet predict that a [Cu-2(mu-S)(2)](0) core is a stable product of 2-electron reduction of the [Cu-2(mu-eta(2):eta(2)-S-2)](2+) unit. Exchange of the disulfido ligand was discovered upon reaction of a (mu-eta(2): eta(2)-disulfido)dicopper complex with a Cu(I) reagent.