Block copolymers on basis of poly(oxanorbornenes) bearing functional moieties in their side-chains are prepared via a combination of ROMP-methods and 1,3-dipolar-"click"-reactions. Starting from N-substituted-omega-bromoalkyl-oxanorbornenes and alkyl-/perfluoroalkyl-oxanorbornenes, block copolymers with molecular weights up to 25,000 g mol(-1) were generated. Subsequent nucleophilic exchange-reactions yielded the block-copolymers functionalized. with omega-azidoalkyl-moieties in one block. The 1,3-azide/alkine-"click" reactions with a variety of terminal alkynes in the presence of a catalyst system consisting of tetrakis(acetonitrile)hexafluorophosphate copper(I) and tris(1-benzyl-5-methyl-H-1-[1,2,3]triazol-4-ylmethyl)-amine furnished the substituted block copolymers in high yields, as proven by NMR-spectroscopy. The resulting polymers were investigated via temperature-dependent SAXS-methods, revealing their microphase separated structure as well as their temperature-dependent behavior. The presented method offers the generation of a large set of different block-copolymers from only a small set of starting materials because of the high versatility of the "click" reaction, thus enabling a simple and complete functionalization after the initial polymerization reaction. (c) 2006 Wiley Periodicals, Inc.