The reaction of poly(methyl methacrylate) (PMMA), poly(i-butyl methacrylate), poly(2-hydroxyethyl methacrylate), and polymethacrylonitrile bearing organotellurium, organostibine, and organobismuthine omega-living polymer end groups with 2,2,6,6-tetramethylpiperidine 1-oxy (TEMPO) under thermal or photochemical conditions gave the corresponding omega-vinylidene functionalized polymethacrylates and polymethacrylonitrile with high end group fidelity. Treatment of the PMMA with ethyl 2[(tributylstannyl)methyl]acrylate also gave a PMMA bearing the same to-vinylidene end functionality. (1)H NMR, GPC, MALDI TOF MS, and thermogravimetric analyses revealed the highly controlled and defined structure of poly(alkyl methacrylate)s and polymethacrylonitrile in terms of molecular weight, molecular weight distribution, and the omega-polymer end structure. (C) 2009 Elsevier Ltd. All rights reserved.