Poly(propylene glycol)‐b‐poly(4‐bromostyrene) (PPG‐b‐PBS) block copolymers with different hydrophobicities have been synthesized by ATRP, which are used as micelle templates for the synthesis of nanostructured luminescent spheres by catalystic emulsion polymerizaton. The optical properties of the nanospheres can be tuned by adding 4,7‐dibromo‐2,1,3‐benzothiadiazole (BTH) in emulsion polymerization process. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]