The synthesis, via ring opening metathesis polymerisation, and hydrogenation, using diimide, of a series of copolymers of (+/-)-5-trifluoro-methylbicyclo[2.2.1]hept-2-ene with cyclopentene is described. The products were characterised via a detailed analysis of their H-1, C-13 and F-19 NMR spectra, along with thermal and GPC analysis. Hydrogenation using diimide resulted in a significant lowering of the glass transition temperatures of the copolymers. (C) 2003 Elsevier B.V. All rights reserved.