5-Ethynyl-2,2-bipyridine (1; bpyC&3bond; CH) polymerized in the presence of catalytic amounts of [RhF(COD)(PPh3)] or [Rh(mu-OH)(COD)](2) (COD - 1,5-cyclooctadiene) in 74-91% yields. In contrast, [Rh(mu-X)(NBD)](2) (X = Cl or OMe; NBD = norbornadiene) did not catalyze the polymerization of 1 or gave low yields of the polymer. The obtained polymer, poly(5-ethynyl-2,2'-bipyridine) [2; (bpyC=CH)(n)], was highly stereoregular with a predominant cis-transoidal geometry. Random copolyacetylenes containing the 2,2'-bipyridyl group with improved solubility in organic solvents were obtained by the treatment of a mixture of 1 and phenylacetylene (3) or 1-ethynyl-4-n-pentyl-benzene with catalytic amounts of [RhF(COD)(PPh3)]. A block copolymer of 1 and 3 was prepared by the addition of 1 to a poly(phenylacetylene) containing a living end. The reaction of 2 with [MO(CO)(6)] produced an insoluble polymer containing [MO(CO)(4)(bpy)] groups, whereas with [RuCl2(bpy)(2)] or [Ru(bpy)(2) (CH3COCH3)(2)](CF3SO3)(2), it gave soluble metal-polymer complexes containing [Ru(bby)(3)](2+) groups. (c) 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3167-3177, 2005.