Triangular [Mo3S4] clusters are known to serve as platforms to accommodate a metal atom M, furnishing cubic [Mo3S4M] clusters. In this study, three [Mo3S4] clusters supported by eta(5)-cyclopentadienyl (Cp-R) ligands, [(Cp3Mo3S4)-Mo-R](+) (Cp-R = C5Me4SiMe3, C5Me4SiEt3, and C5Me4H), were synthesized via half-sandwich molybdenum chlorides (CpMoCl4)-Mo-R. In the cyclic voltammogram of the [Mo3S4] cluster having C5Me4H ligands, a weak feature appeared in addition to the [(Cp3Mo3S4)-Mo-R](0/-) redox process, indicating the interaction between [(Cp3Mo3S4)-Mo-R](-) and the [(NBu4)-Bu-n] cation of the electrolyte, while such a feature was less significant for the C5Me4SiR3 variants. The [Mo3S4] clusters with bulky C5Me4SiR3 ligands were successfully applied as platforms to accommodate an Fe atom to furnish cubic [Mo3S4Fe] clusters. On the other hand, the corresponding reactions of the less bulky C5Me4H analogue gave complex mixtures.