Rare examples of (μ-η2:η2-disulfido)dicopper complexes have been prepared from Cu(I) and Cu(II) complexes of β-diketiminate and anilido−imine supporting ligands. A novel byproduct derived from sulfur functionalization of the methine position of a β-diketiminate ligand was identified. DFT calculations on [(LCu)2X2] (L = β-diketiminate, X = O or S) complexes rationalize the absence of a bis(μ-sulfido)dicopper isomer, [Cu2(μ-S)2]2+, in the synthetic reactions, yet predict that a [Cu2(μ-S)2]0 core is a stable product of 2-electron reduction of the [Cu2(μ-η2:η2-S2)]2+ unit. Exchange of the disulfido ligand was discovered upon reaction of a (μ-η2:η2-disulfido)dicopper complex with a Cu(I) reagent.