A review. Covalent organic frameworks (COFs) are promising organic materials that can be designed and synthesized from small mols. like building blocks with photo-functional properties. Photocatalysis using photo-responsive COFs is a relatively new field that has been developed in the last five years. Here, we recent progress in COF-based photocatalysis for environmental and energy applications. The first part of this focuses on synthesis of COFs, including basic processes for increased solubility to facilitate handling, including exfoliation methodologies, and work towards further improvement of COF-based photocatalytic processes. Time-resolved absorption measurement techniques and theor. calculations to understand the carrier dynamics of COFs for photocatalytic process are also ed. The main focus of the is to summarize the practical applications of COF-based photocatalysts in the environmental and energy fields. Important examples such as photoinduced oxidation reactions, hydrogen generation, and CO2 reduction reactions are covered. Finally, we conclude this with prospects for COF-based photocatalysts. This will serve as a guide for understanding recent progress in COF-based photocatalysis.