The (CH3)(2)Si[CpMo(CO)(3)](2) complex (1) was synthesized and used to explore ring-opening polymerization (ROP) as a method to prepare high molecular weight polymers containing Mo-Mo bonds along their backbones. Attempts to initiate ROP of 1 using n-BuLi or PtCl2 did not yield any polymers. The X-ray crystal structure of 1 shows that the Si center is not strained, and it is suggested that no ROP occurred because 1 is less strained than other organometallic ROP monomers, such as the silicon-bridged ferrocenophanes. Thermal ROP (TROP) of 1 was successful and yielded a polymer (M (w) = 210,000 g mol(-1)) containing both Mo-Mo single bonds and Moa parts per thousand Mo triple bonds. When CO(g) is passed over the polymer in the solid state, the Moa parts per thousand Mo triple bonds are converted to Mo-Mo single bonds. Attempts to increase the yield of the TROP polymer by increasing the reaction times led to polymer decomposition. The decomposition is likely caused by the weakness of the Mo-Mo bond, cleavage of which causes the polymer to degrade.