Preparation of Emissive Metallacycles/Cages and Their Recent Uses and Applications

By selectively combining organic donors with metal centers, a class of metal–organic cycles/cages (MOCs) with unique shapes and sizes can be synthesized. Due to their tunable structures and physicochemical properties, these materials hold significant potential for applications in optoelectronic devices, chemical sensing, and biomedical fields. This review highlights recent advancements in MOC research across various domains, including luminescence, sensing, resonance fluorescence energy transfer, and biomedical materials. Additionally, this review explores the applications of MOCs in molecular recognition, host–guest chemistry, and the design of functional materials, demonstrating their unique advantages in developing smart responsive systems and multifunctional integrated materials. This review summarizes recent progress in the field over the past five years.