2D sp ² carbon‐conjugated covalent organic frameworks: photocatalytic platforms for solar energy conversion

Abstract The unique fully conjugated architecture and tunable electronic properties of 2D sp 2 carbon‐conjugated covalent organic frameworks (sp 2 c‐COFs) have established them as promising photocatalysts. This review systematically summarizes the synthetic strategies, photocatalytic applications and performance modulation mechanisms of sp 2 c‐COFs, and provides an outlook on future research directions. First, we introduce the main synthetic methods for sp 2 c‐COFs, including Knoevenagel condensation, Aldol condensation and Horner‐Wadsworth‐Emmons reactions. Subsequently, we discuss in detail their photocatalytic applications in H 2 evolution, CO 2 reduction, H 2 O 2 production, pollutant degradation, and selective organic transformations. Additionally, this review comprehensively discusses key photocatalytic regulation mechanisms, revealing how molecular design strategies can precisely control electronic structures, active site accessibility, and interfacial charge dynamics to enhance photocatalytic performance. Finally, we analyze the current challenges in the field and propose future research directions, including the development of novel synthetic strategies, deeper understanding of photocatalytic mechanisms, and the expansion of their applications in energy and environmental technologies. This work provides fundamental insights into structure–property relationships and paves the way for future photocatalytic systems.