We report a novel fluorescent polyfluorene-containing methacrylate macromonomer (PFMA) and its well-defined copolymers with 2-(dimethylamino)ethyl methacrylate (DMAEMA) [P(PFMA-r-DMAEMA)s] via reversible addition–fragmentation chain transfer (RAFT) polymerization. These copolymers self-assemble into photoluminescent nanoparticles in aqueous solutions and act as an excellent scaffold for the incorporation of various pigments to emit tunable colors, including white, through Förster resonance energy transfer with high quantum yield up to 0.80. The directly cast films of these NPs after evaporation of water exhibit strong colorful emission on both smooth quartz and rough plaster surfaces. The NP aqueous solutions are ready for ink-jet printing to produce exquisite fluorescent pictures.