Electron Donor–Acceptor Interactions Enabling Aqueous Synthesis of Covalent Organic Frameworks with Unprecedented Crystallinity and Porosity for Water Extraction from Arid Air

Abstract The synthesis of covalent organic frameworks (COFs) often relies on extensive usages of organic solvents and struggles to achieve high crystallinity and porosity due to kinetic challenges and monomer insolubility in water. Here, we leverage electron transfer between electron‐rich catalysts and electron‐deficient monomers to realize in‐water synthesis of highly crystalline COFs. Forming electron donor–acceptor (EDA) complexes enables hydrophobic monomers soluble in water and enhances reaction reversibility, scalably producing COFs with diverse linkages and surface areas reaching the theoretical limits. Water promotes electron transfer, lowering energy barriers, and leading to crystallinity far beyond that of COFs synthesized in organic solvents. The EDA‐synthesized COFs exhibit excellent stability, and exceptional performance in water extraction from arid air (0.65 g g −1 at 30% relative humidity). By resolving longstanding challenges in COF synthesis—crystallinity, porosity, and scalability—this work establishes a paradigm for synthesizing high‐quality crystalline frameworks, advancing their applications in sustainable technologies.