Polymerization of 2-methylvinylacetylene (VA) is a selective, anion-initiated process affording poly(2-methylvinylacetylene) (PVA) with M(w) of 1600-3060 and a polydispersity of 1.5-1.7. The acetylenic groups of PVA can be further functionalized by palladium(II)-catalyzed hydrocarboxylation, hydroesterification, and iodoarene/CO coupling reactions to give new polymers containing pendant functional groups of alpha,beta-unsaturated carboxylic acids, esters, and ketones, respectively The catalytic processes used here provide unique methods to synthesize these polymers in a stereocontrolled and stereoselective manner. Using the Pd(OAc)(2)-dppb catalytic system, high conversions (100%) of the pendant acetylenic groups of PVA were realized, affording alpha,beta-unsaturated acid- or ester-containing polymers with >80% selectivity at the terminal position. These polymers are not available by direct polymerization of functionalized monomers. Gel permeation chromatography indicated that neither chain scission nor cross-linking takes place during the catalytic reactions. The terminal acetylenic groups of PVA could also couple with iodoarenes and CO, in the presence of either PdCl2(PPh(3))(2) or Pd-clay as the catalyst and Et(3)N as base, affording branched polyketones.