Aggregation-induced emission (AIE)-active polymer prodrug nanoparticles were readily prepared by growing short, well-defined polymer chains from an AIE dye by nitroxide-mediated polymerization, followed by co-nanoprecipitation of the resulting conjugates with similarly constructed anticancer polymer prodrugs. The nanoparticles had sharp fluorescence signal offering excellent imaging ability in living cells and their intra cellular localization to be accurately monitored.