A well-defined and monofunctional poly(3-hexylthiophene)-based (P3HT) macroinitiator has been obtained through a clean, simple, and an efficient multistep synthesis process. The macroinitiator is obtained via intermolecular radical 1,2-addition onto an ?-acrylate-terminated P3HT macromonomer. In a second step, well-defined rod-coil block copolymers were obtained by nitroxide-mediated radical polymerization (NMRP) using the so-called Blocbuilder (R). The polymerization was found to be controlled with various monomers such as styrene, isoprene, 4-vinylpyridine, or methyl acrylate. This process constitutes a very promising way to obtain versatile and clean materials for organic electronics. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012