The ionic liquids n-butylpyridinium tetrafluoroborate [bupy]BF4 and 1-n-butyl-3-methylimidazolium tetrafluoroborate [bmim]BF4 have been used as solvents for the Rh(l) catalyzed phenylacetylene polymerization in the presence of triethylamine as co-catalyst, obtaining high yields of poly(phenylacetylene). The complexes used are (diene)Rh(acac) and [(diene)RhCl](2) [diene: 1,5-cyclooctadiene or norbomadiene]. The (nbd)Rh(acac) complex in both ionic liquids can be recycled without significant loss in activity. Molecular weights in the range between 55,000 and 200,000 Da have been obtained by GPC. (C) 2002 Elsevier Science B.V. All rights reserved.