Conductive metal-covalent organic frameworks for electrochemical and sensing applications: Structural design and charge transport mechanisms

Metal-covalent organic frameworks (MCOFs) are an emerging class of porous crystalline materials that combine structural tunability with redox-active metal centers, enabling applications in electrocatalysis, energy storage, and chemical sensing. This review presents a comprehensive overview of recent advances in improving the electrical conductivity of MCOFs, with emphasis on molecular design, charge transport mechanisms, and performance benchmarking. Strategies to achieve intrinsic and extrinsic conductivity are categorized into (i) extended π-conjugation, (ii) incorporation of electron-scheme based on charge-transfer resistance (R ct ) are introduced to enable standardized comparisons across systems. We highlight application-specific breakthroughs in hydrogen and oxygen evolution reactions, carbon and nitrogen reduction, urea oxidation, metal-air batteries, and biosensing. Finally, we discuss important challenges - such as low intrinsic conductivity, solvent toxicity, and synthetic scalability - and suggest future directions to accelerate the deployment of high-conductivity MCOFs in real-world technologies. Core guidelines and synthetic approaches for engineering metal-covalent organic frameworks (MCOFs) with exceptional electrical conductivity target their application in diverse electrochemical systems. Central to these designs are the extended π-conjugated networks and the incorporation of electron-rich d-band metal centers, both of which markedly improve the frameworks' native conductivity and enable operation at high current densities. In addition, coupling MCOFs with external conductive components - such as carbon nanotubes (CNTs), poly(3,4-ethylenedioxythiophene) (PEDOT), or metallic nanoparticles - creates synergistic pathways for charge transport, further elevating the composite's conductivity and enhancing its performance in electrochemical processes. • Precision synthesis of conductive MCOFs: Tailored molecular structures to achieve metal-covalent organic frameworks (MCOFs) with improved electron mobility. • Core conductivity mechanisms: Influence of extended π-conjugation, electron-rich metal centers, heteroatom doping, and hybridization with conductive polymers. • Electrochemical applications: Enhanced performance in energy conversion, electrocatalysis, and chemical sensing. • Future perspectives: Strategies to adress structural, synthetic, and scalability challenges for sustainable MCOF development.