We report the syntheses and uses of versatile chain transfer agents (CTAs) that produce well-controlled macromolecular architectures with specific chain-end functionalities, via reversible addition fragmentation chain transfer (RAFT) polymerization). Examples of architectures are given, including amphiphilic copolymers and block copolymers incorporating a biodegradable block. These CTAs are also used for the grafting of poly(styrene), poly(methyl methacrylate) and poly(methyl acrylate) from cotton.