As previously reported , NDI-PS was first synthesized via ATRP initiated by NDI-diBr. By varying the monomer/initiator feed ratios, different MWs (3000 to 13,000 g mol -1 ) were achieved. The end-group transformation was performed according to the reported method , as described below. In a Schlenk flask, AgClO 4 (3.0 eq.) was added; in another Schlenk flask, NDI-PS with the desired MW (1.0 eq.) and polycyclic aromatic alcohol (8-20 eq.) were added. The two flasks were evacuated for 1 h, followed by 3 cycles vacuumargon refill. Then, the polymer/alcohol mixture was dissolved in extra-dry toluene under argon, and the solution under argon was transferred into the flask with AgClO4. The flask was placed in an oil bath at 40°C (for NDI-PS-Bp and NDI-PS-Fluo) or 25 °C (for others) with stirring overnight. The residue was then successively dissolved in THF, filtered through a column of basic alumina, precipitated 2-3 times in methanol, and finally dried under vacuum overnight. Final products were obtained and characterized by H NMR spectroscopy (Figures ), GPC (Figure ), and powder X-ray diffraction (Figure ). Note that, vinyl benzene groups may form during the debromination process, as indicated by the signals at ~6.1-6.2 ppm in H NMR spectra (Figures ) and the multimodal peaks in the GPC spectra of NDI-PS-Ant and NDI-PS-Py (Figure ). The resultant multiple polymer species may account for the less uniform distributions of the emission spectrum and fluorescence decay curves, compared to that of the copolymer system.