This review highlights the luminescent and unique photophysical properties of covalent organic frameworks. Their potential use in applications related to chemical sensing, photocatalysis, and optoelectronics are discussed.

The development of high-performance organic electrodes for potassium-ion batteries (KIBs) is attracting interest due to their sustainability and low costs. However, the electrolyte systems and moieties that generally proved to be successful in high-performance Li-ion batteries have found relatively little success in KIBs. Herein, two alkynyl-based covalent organic frameworks (COFs) containing 1,3,5-tris(arylethynyl)benzene (TAEB) and dehydrobenzoannulene (DBA) units are utilized as bulk anode materials for KIBs in a localized high-concentration electrolyte. TAEB-COF provides a high capacity value of 254.0 mAh g −1 at ∼100% efficiency after 300 cycles, and DBA-COF 3 provides a capacity of 76.3 mAh g −1 with 98.7% efficiency after 300 cycles. DFT calculations suggest that the alkynyl units of TAEB-COF facilitate the binding of Kions through both enthalpic and geometric driving forces, leading to high reversible capacities.

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Thermal management is essential for maintaining the optimal performance of electronic devices. Although covalent–organic frameworks (COFs) have emerged as a platform for gas and energy storage applications, their thermal transport properties are greatly understudied. Herein, we report the thermal conductivities of three benzobisoxazole (BBO)-linked COFs with nanpores ranging from 1.3 to 2.5 nm over a wide temperature range (80–300 K) using the longitudinal, steady-state heat-flow method. In doing so, thermal conductivity values as high as 0.677 W m–1 K–1 at 300 K were obtained, and no relationship between the thermal conductivity and pore size was observed. These results were supported by density functional theory calculations. The thermal conductivities of the BBO-COFs doped with poly­(3-hexylthiophene) were also investigated. The BBO-COFs could be useful as ultralow-k materials for thermal management applications.