COFs in Action: Advanced Approaches for Monitoring Uranium, Mercury, Lead, and Nitro Compounds in Environmental Contaminants.

Covalent organic frameworks (COFs) are crystalline, porous polymers with tunable architectures, high surface areas, and robust chemical stability, making them promising platforms for chemical sensing. This review surveys recent advances in luminescent COFs (LCOFs) for the selective detection of hazardous contaminants via fluorescence-based mechanisms, including photo-induced electron transfer and energy transfer. Representative studies discuss ultra-low detection limits for UO22+, Hg2+, and Pb2+, along with rapid response times, high adsorption capacities, and strong recyclability. Sensitivity and selectivity are further enhanced through functionalization strategies such as amidoxime grafting, lanthanide incorporation, and linkage engineering. Beyond actinide sensing, LCOFs have demonstrated effectiveness toward mercury, lead, nitro-aromatic explosives, and biological markers, underscoring their functional versatility. Despite these advances, key challenges persist, including scalable synthesis, structural stability in complex matrices, and integration into deployable sensing devices. Future progress leveraging hybrid material systems, computation-guided design, and portable detection platforms could position LCOFs as transformative tools for environmental monitoring, nuclear safety, and public health protection.