Fluorescent organic cages and their applications

Organic cages are an emerging subclass of crystalline porous materials with structural tunability, modularity, and processibility, having exhibited potential in applications such as molecular recognition, gas adsorption, catalysis, and other fields. Fluorescence can be easily introduced into organic cages by incorporating fluorescent building blocks. The diversity of fluorescent building blocks and well-developed cage construction methods allowed the booming of fluorescent organic cages. More importantly, incorporating fluorescent properties into organic cages can further expand their application areas, especially in fields such as biological imaging and luminescent devices. The cavity of organic cages endows them with extra confined space to accommodate bioactive species or drugs compared to fluorescent small molecules. Compared to their framework counterparties, organic cages with well-characterized structures exhibit better processability, allowing their use in applications beyond solutions. In this review, we summarize the latest progress on fluorescent organic cages, focusing on their construction methods and the recent advances in their applications.