The synthesis and redox properties are presented for the electron-rich bis(monothiolate)s Fe-2(SR)2(-) (CO)(2)(dppv)(2) for R = Me ([1](0)), Ph ([2](0)), CH2Ph ([3](0)). Whereas related derivatives adopt C-2-symmetric Fe-2(CO)(2)P-4 cores, [1](0)-[3](0) have C-s symmetry resulting from the unsymmetrical steric properties of the axial vs equatorial R groups. Complexes [1](0)-[3](0) undergo 1e(-) oxidation upon treatment with ferrocenium salts to give the mixed valence cations [Fe-2(SR)(2)(CO)(2)(dppv)(2)](+). As established crystallographically, [3](+) adopts a rotated structure, characteristic of related mixed valence diiron complexes. Unlike [1](+) and [2](+) and many other [Fe-2(SR)(2)L-6](+) derivatives, [3](+) undergoes C-S bond homolysis, affording the diferrous sulfido-thiolate [Fe-2(SCH2Ph)(S)(CO)(2)(dppv)(2)](+) ([4](+)). According to X-ray crystallography, the first coordination spheres of [3](+) and [4](+) are similar, but the Fe-sulfido bonds are short in [4](+). The conversion of [3](+) to [4](+) follows first-order kinetics, with k = 2.3 X 10(6) s(-1) (30 degrees C). When the conversion is conducted in THF, the organic products are toluene and dibenzyl. In the presence of TEMPO, the conversion of [3](+) to [4](+) is accelerated about 10X, the main organic product being TEMPO-CH2Ph. DFT calculations predict that the homolysis of a C-S bond is exergonic for [Fe-2(SCH2Ph)(2)(CO)(2)(PR3)(4)](+) but endergonic for the neutral complex as well as less substituted cations. The unsaturated character of [4](+) is indicated by its double carbonylation to give [Fe-2(SCH2Ph)(S)(CO)(4)(dppv)(2)](+) ([5](+)), which adopts a bioctahedral structure.