Visualization of supramolecular assembly by aggregation-induced emission

Supramolecular architectures are constructed by the self-assembly of small building blocks via the use of metal-ligand coordination, pi-pi stacking interactions, hydrogen bonding, host-guest interactions, and other noncovalent driving forces, which confer unique dynamic reversibility and stimulus responsiveness to the supramolecular materials and also lead to the demand of expensive and complex equipment for the characterization of supramolecular assembly processes. Fortunately, the self-assembly processes bring the monomeric chromophores together, offering possibilities to establish ties between the supramolecular assembly and aggregation-induced emission (AIE) techniques. Compared to conventional luminescent molecules, AIE luminogens (AIEgens) exhibit significant fluorescence enhancement upon the restriction of molecular motions, thus displaying the advantages of signal amplification and low background noises. Given the above, the real-time, sensitive, and in situ visualization of the formation of self-assemblies and their stimuli responsiveness based on AIE becomes accessible. Here, we review recent works that encompass the visualization of supramolecular assembly-related behaviors by means of AIE characteristics of chromophores. The organization of this review will be by different types of supramolecular architectures, including metallacycles/cages, micelles/vesicles, supramolecular polymers, and supramolecular gels. An overview of future opportunities and challenges for the real-time monitoring of supramolecular assembly by AIE is also provided.