Polycarbostannanes have been successfully synthesized via acyclic diene metathesis chemistry utilizing both a well-defined molybdenum akylidene and an aryloxo tungsten "classical" catalyst system. In the case of the well-defined catalyst, the polymerization proceeds smoothly to produce linear polymer which is characterized by proton, carbon, and tin NMR. Molecular weights of about 16000 g/mol can be produced. The production of a polycarbostannane via classical metathesis chemistry is just as facile, producing molecular weights comparable to the well-defined system, and in this case, the monomer performs as both the monomer and the cocatalyst species.