A unique Co(II)- and Fe(II)-mediated complete desulfurization of disulfides of the type RS-SR and RC(O)S-SC(O)R to yield the corresponding alcohols (ROH) and carboxylic acids (RCOOH), respectively, along with the formation of a dicobalt(II)/diiron(II)-hydrosulfide complex, [M-2 (PhBIMP)(mu(2)-SH)(DMF)](2+) (M = Co, Fe), has been demonstrated. This new desulfurization reaction involves cleavage of both C-S and S-S bonds, where the cleavage of the S-S bond (presumably two-electron reduction of the S-S bond) may generate two-electron-oxidized dicobalt(III)/diiron(III) species, [M-2(III) (PhBIMP)(H2O) 2 (DMF)(2)](5+) (M = Co, Fe), in solution. While the generation of such a solvent- and/or H2O-coordinated dicobalt(III) species in the reaction solution could not be established beyond a doubt, formation of the diiron(III) species [Fe-2(III) (PhBIMP)(H2O)(2) (DMF)(2)](5+) according to the proposed reaction mechanism has been confirmed by a combination of mass spectrometry and UV-vis spectroscopy in comparison with an authentic sample, synthesized directly by an independent procedure using Fe(ClO4)(3)center dot xH(2)O. Interestingly, a comparative study using different types of disulfides and the molecular structure determination of a key reaction intermediate, [Fe,(PhBIMP)(MeCOSS)](2+), generated via the cleavage of only one C-S bond of MeC(O)S-SC(O)Me, demonstrates that the C-S bond cleavage step precedes the S-S bond cleavage step during the Fe(II)-mediated desulfurization of disulfides.