Phenylacetylene (PA) derivatives having two polar groups (ester, 2a-d; amide, 4) or one cyclic polar group (imide, 5a-c) were polymerized using (nbd)Rh+[(eta(6)- C6H5)B-(C6H5)(3)] catalyst to afford high molecular weight polymers (similar to 1 x 10(6) - 4 x 10(6)). The hydrolysis of ester-containing poly(PA), poly(2a), provided poly(3,4-dicarboxyPA) [poly (3)], which could not be obtained directly by the polymerization of the corresponding monomer. The solubility properties of the present polymers were different from those of poly(PA) having no polar group; that is, poly(2a)-poly(2d) dissolved in ethyl acetate and poly(4) dissolved in N,N-dimethylformamide, while poly(PA) was insoluble in such solvents. Ester-group-containing polymers [poly(2a)-poly(2d)] afforded free-standing membranes by casting from THF solutions. The membrane of poly(2a) showed high carbon dioxide permselectivity against nitrogen (PCO2/PN2 = 62). (c) 2006 Wiley Periodicals, Inc.