AB block copolymers of styrene and 4-nitrostyrene have been prepared. The 4-nitrostyrene monomer was synthesized by the nitration of 2-bromoethylbenzene, followed by dehydrobromination, and was purified by sublimation. The polymerization of styrene in tetrahydrofuran was initiated with s-butyllithium and the ’living’ polystyryl anion was used to initiate the polymerization of 4-nitrostyrene. Block copolymer in the product was separated from polystyrene homopolymer by a fractionation procedure. The formation of well-defined block copolymers was verified by characterization of the polymers with respect to composition and molecular weight distribution and by studies of their micellization behaviour. Micelles were shown to form in toluene, a selectively bad solvent for poly(4-nitrostyrene). Differential scanning calorimetry indicated a microdomain structure in the solid state.