As a kind of molecular materials that have infinite metalligand backbones connected by coordination bonds,owing to the diversity of organic bridging ligands and flexibility of metal ions and organic bridging ligands in coordination bonding and geometry,coordination polymers can be expected to have versatile structures and properties.Though the term "coordination polymer" first appeared in the 1960s,the investigation in this field was not active until two decades ago.Since 1990,chemists gradually discovered many interesting coordination polymers with novel structures,especially porous coordination polymers (PCPs) and their structure-based properties.Coordination polymers have then been emerging as a topical research field in crystal engineering,solid-state chemistry,and materials science.