Exosome‐Mimetic Supramolecular Vesicles with Reversible and Controllable Fusion and Fission**

Abstract The fusion and fission behaviors of exosomes are essential for the cell‐to‐cell communication. Developing exosome‐mimetic vesicles with such behaviors is of vital importance, but still remains a big challenge. Presented herein is an artificial supramolecular vesicle that exhibits redox‐modulated reversible fusion‐fission functions. These vesicles tend to fuse together and form large‐sized vesicles upon oxidation, undergo a fission process and then return to small‐sized vesicles through reduction. Noteworthy, the aggregation‐induced emission (AIE) characteristics of the supramolecular building blocks enable the molecular configuration during vesicular transformation to be monitored by fluorescence technology. Moreover, the presented vesicles are excellent nanocarrier candidates to transfer siRNA into cancer cells.