The flexibility of synthetic chemistry in emission tuning of the NDI polymer platform was further explored by introducing aromatic functional groups to a pre-synthesized NDI-PS via end group engineering. We first functionalized NDI-PS with MW ranging from 3000 to 13,000 g mol -1 with 1-pyrenemethanol (PyOH) via a onestep displacement reaction catalyzed by AgCO4 (Figure ) . As shown in Figure , the emission color of the resulting NDI-PS-Py changed from blue to pink with decreasing MW of the original NDI-PS. Moreover, to explore color tunability with extended π-conjugation degree, we also synthesized a block copolymer of styrene and VPy using NDI-PS (MW = 3000 g mol -1 ) as the macroinitiator, followed by a debromination reaction to generate vinylpyrene end groups. No substantial difference in solid-state emission was observed before and after debromination (Figure ). Subsequently, we functionalized NDI-PS of varied chain lengths with various commercially available polycyclic aromatic alcohols, including 9-fluorenemethanol (FluoOH), 4biphenylmethanol (BpOH), 1-naphthalenemethanol (NaphOH), and 9-anthracenemethanol (AntOH), yielding NDI-PS-Fluo, NDI-PS-Bp, NDI-PS-Naph, and NDI-PS-Ant, respectively (Table ). With the conversion of end group transformation mostly exceeding 30% (Table ), the functionalized NDI polymers showed blue emission at the highest MW (e.g., 13,000 g mol ) and redshifted fluorescence upon lowering the MWs, as indicated in Figure . Consistent with the corresponding NDI copolymers, AIE activities were observed (Figure ) for majority of the polymers, whereas bimodal emission spectra were obtained for NDI-PS-Py and NDI-PS-Ant.