Ruthenium catalyzed step growth copolymerization of 4'-methoxyacetophenone or 4'-phenoxyacetophenone and a,omega-dienes such as 1,3-divinyltetramethyldisiloxane or 3,3,6,6-tetramethyl-3,6-disila- 1,7-octadiene give copolymers which have respectable molecular weights. The synthesis and characterization of these copolymers is reported. Higher molecular weight copolymers are quite thermally stable.