The reaction of H2Se with Cr(h-C5H4Me)2 gives a new cubane cluster [Cr4(m3-Se)4(h-C5H4Me)4] with a yield of 90%. The reaction of LiSeH with Mo2(h-C5H4Pr)2(m-Cl)4 gives the other cluster [Mo4(m3-Se)4(h-C5H4Pr)4]. The x-ray single crystal structural anal. confirms the cubane-like structure of the molybdenum cluster. The cyclic voltammogram data show that the neutral compounds undergo reversible sequential 2-electron oxidation, and the photoelectron spectroscopic study indicates these clusters to be highly electron rich.