An amphiphilic block copolymer composed of poly(ethylene oxide) and poly(methacrylate ester) bearing a donor-acceptor-type 2,5-diarylthiazole in the side chain is prepared by atom-transfer radical polymerization. The precursor 2,5-diarylthiazole monomer is prepared by transition-metal-catalyzed CH arylation reactions. A thin film of the block copolymer formed by spin coating exhibited nanoscale phase separation with homeotropically oriented domains, while a film formed by the friction transfer method showed domains with homogeneous orientation confirmed by AFM. Spectroscopic studies of the film, utilizing the luminescent characteristics of 2,5-diarylthiazole, showed polarized light emission as a result of the liquid crystalline ordering.