The reactions of the (Et4N)(2)[(Cl-4-cat)(MeCN)MoFe3S4Cl3] (1) cluster with Fe(PP)(2)Cl-2 (PP = depe (bis(1,2diethylphosphino)ethane) or dmpe (bis(1,2-dimethylphosphino)ethane)) produced the {(Cl-4-cat)MoFe3S4(PP)(2)Cl}(2-)(mu-pp) (pp = depe (111) or dmpe (V)) singly bridged double cubanes. The reactions of I with the same bidentate phosphine ligands in the presence of NaBPh4 also produced III and the {(Cl-4-cat)MoFe3S4(dmpe)(2)}(2)(mu-S)(mu-dmpe) (VI) doubly bridged double cubane, respectively. The byproduct (BPh4)[Fe(dmpe)(2)(MeCN)Cl] (VII) has been isolated from the reaction mixture and crystallographically characterized. The depe analogue of VI, {(Cl-4-cat)MoFe3S4(depe)(2)}(2) mu-S)(mu-depe) (IV), has been successfully prepared from III in the presence of excess Li2S. Similar reactions with (Et4N)(2)[Fe4S4(SPh)(4)] (VIII) have resulted in the formation of the neutral Fe4S4(depe)(2)(SPh)(2) (IX) cluster. The chloride analogue of IX, Fe4S4(depe)(2)Cl-2 (XI), has been obtained by a reaction of IX with benzoyl chloride. The crystal and molecular structures of 111, VI, VII, and XI have been determined by single-crystal X-ray crystallography. The electrochemical and spectroscopic properties, including the Mossbauer spectra of the new clusters, have been determined and analyzed.