Contemporary polymer science requires, more than ever, simple and efficient chemical reactions for constructing complex macromolecular or supramolecular structures. The present feature article highlights our recent efforts to develop modular synthetic platforms in macromolecular synthesis. As examples, the macromolecular engineering possibilities of two "click" reactions (i) the copper-catalyzed cycloaddition of azides and terminal alkynes and (ii) the radical addition of mercaptans onto vinyl double bonds are discussed in detail herein. (C) 2007 Elsevier Ltd. All rights reserved.