Copolymers with 2-aceto-1,3-phenanthrenylene units in the chain have been directly prepared by Ru catalyzed step-growth copolymerization of 2-acetyl phenanthrene and alpha,omega-dienes such as 1,3-divinyltetramethyldisiloxane. Copolymers which incorporate 2-aceto-1,3-phenanthrenylene units possess higher T(g)s and increased thermal stability compared to analogous copolymers which have 2-aceto-5-phenyl-1,3-phenylene(biphenyl) or 2-aceto-1,3-phenylene units. Fluorescence spectra of these copolymers have been obtained.