Photothermal Catalytic Synthesis of Sulfonic Acid Functionalized Covalent Organic Framework Achieved by COF‐to‐COF Transformation for Photocatalysis

Abstract Although photothermal catalysis is a clean, efficient, and green approach to access organic products, its application in the synthesis and transformation of covalent organic frameworks (COFs) remains unprecedented. Herein, we report the photothermal catalytic synthesis of C─C bond linked COF under visible light, which can be a reusable photocatalyst to highly promote oxidation of benzyl amines. Furthermore, we have developed a new postsynthetic modification strategy to construct COFs by photoinduced thermally‐driven hydroamination via crystal‐to‐crystal transformation. The obtained COF containing sulfonic acid group showed an excellent catalytic performance in promoting aerobic oxidation of alkyl arenes under mild reaction conditions. These results not only enrich the COF synthetic methodology but also open a new route to access COFs in a green and sustainable way.