Polystyrene prepared by nitroxide-mediated radical polymerization (NMRP) bearing a benzyl chloride on the a-terminus was converted to an azide by S(N)2 displacement, followed by oxidative replacement of the alkoxyamine with a terminal acetylene using ceric ammonium nitrate and propargyl alcohol at the omega-terminus. Macrocyclization using copper(l) catalyzed Huisgen 1,3-dipolar cycloaddition resulted predominately in macrocyclic polymers. Azidation of polystyrene prepared by NMRP upon thermolysis with ethanesulfonyl azide provided partial incorporation of azide in place of the terminal alkoxyamine. (c) 2008 Elsevier Ltd. All rights reserved.