An amino‐core‐substituted naphthalenediimide (NDI) derivative has been synthesized in good yield in two steps. The NDI bearing a diamine moiety undergoes a reversible protonation–deprotonation process, which results in intensity changes in the absorption and emission spectra. This derivative exhibits good photostability, good selectivity, high sensitivity, and is employed to exhibit the pH within the rough endoplasmic reticulum of living cells.

In the present work, two new naphthalene diimide (NDI) amphiphiles, NDI‐N and NDI‐NA, were successfully synthesized and employed to investigate their self‐assembly and optical properties. For NDI‐NA, which contains an amide group, aggregation‐induced emission enhancement (AIEE) was demonstrated in the presence of various ratios of methylcyclohexane (MCH) in chloroform, which led to the visual color changes. This new amide‐containing NDI‐NA amphiphile formed nanobelt structures in chloroform/MCH (10:90, v/v) and microcup‐like morphologies in chloroform/MCH (5:95, v/v). The closure of these microcups led to the formation of vesicles and microcapsules. The structural morphologies gained from the solvophobic control of NDI‐NA were confirmed by various complementary techniques such as infrared spectroscopy, X‐ray diffraction, and scanning and transmission electron microscopy. In the absence of the amide moiety in NDI‐N, no self‐assembly was observed, indicating the fundamental role of H‐bonding in the self‐association process.

Construction of thermodynamically stable nanostructures on the nano- to millimeter scales through noncovalent bonding plays an important role in material science. The self-assembly of tetra-alkylamino core-substituted naphthalene diimides (cNDIs) with variable alkyl chains (C8H17, C12H25, and C16H33) added on to the core leads to the formation of a variety of controlled morphologies and well-defined nanostructures. Such structures include nanorods, vesicular, belts, twisted ribbons, and donutlike morphologies (formed in CHCl3/MeOH and CHCl3/hexane mixtures) generated through solvophobic control. UV/Vis absorption and fluorescence spectroscopy demonstrate molecular aggregation in solution. Furthermore, SEM was employed to visualize the supramolecular self-assembled nanostructures. The growth of these structures is mainly due to packing of hydrophobic alkyl chains and π-π stacking of the cNDI core. The present study paves the way to rational and controlled designs of nanostructures made of optically active dyes (naphthalene diimide); this may open a new avenue towards tuning nanodimensional morphology.

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