On where the size and shape of side chains are altered to influence intermolecular interactions and control aggregation. Differing from moving the linked point of the alkyl chain to the backbone, which will change the electron distribution on the backbone and thus shift the emission at the molecular level, side chain engineering by prolonging the alkyl chain generally will not affect its absorption/emission properties at the molecular level as the chromocenters are intact. However, due to different steric hindrance, the different length of the alkyl chain does affect the molecular packing at aggregate levels, which endows it a valuable strategy to tune the absorption and emission properties at aggregate levels for multiple functions. For example, Yingping