Recent progress of amorphous and glassy coordination polymers

In recent decades, the amorphous state of crystalline coordination polymers (CPs) constructed from metal ions and molecular bridging ligands via coordination bonds, has received a lot of attention as an emerging class of materials. Among them, only a few undergo vitrification and demonstrate glassy behavior. Opportunities for discovering unique functionality in amorphous and glassy CPs have been demonstrated with potential advantages of isotropic structure, grain-boundary free structure, variable pore distribution, defect engineering, and transparency. This review begins by introducing the background and important discoveries of amorphous and glassy CPs. The amorphization method and essential characterization techniques are discussed for understanding the structure and functionality of amorphous and glassy CPs. We also review the current stage of properties and applications in ionic, mechanical, magnetic, thermodynamic, porosity, biomedical, optics, and catalysis. We finally conclude by presenting current challenges and perspectives on future research directions.