Construction of crystalline homo/heteroaggregation at micro/nanometer level from organic π‐conjugated systems is of great importance because the controllable morphologies (i.e., size, shape, and dimension) could provide diverse optoelectronic properties for different applications in the electrooptical devices. In this review, we summarize our recent progress in the self‐assembly of micro/nanostructures of organic π‐conjugated molecules via the heteroaggregation and homoaggregation strategies. We also discuss various factors (i.e., temperature, solvents, and surfactants) that affect the aggregation process through a surfactant‐assisted reprecipitation method. Moreover, their physical properties and possible applications in electronics and biofields are illustrated.

A series of twistacene-functionalized dendrimers were successfully synthesized and characterized. The model molecule DBPy has a twisted configuration with a torsional angle of 27.69° between pyrene and naphthalene units. The resulting compounds TPPh, TTPy, OTPy and TOPhP can self-assemble into organic nanoparticles through re-precipitation method and emit strong blue, cyan, green and red fluorescence in water, respectively. Additionally, the obtained multicolor nanoparticles showed low cytotoxicity and good photostability that selectively flow into the membrane and cytoplasm of HeLa cells, indicating the feasibility and efficiency in fluorescence imaging. This study might be a new avenue for the design of three-dimensional branched conjugated molecule and specific location imaging in living cell.