Photocatalytic carbon dioxide (CO2) reduction offers a promising route for converting greenhouse gas into value-added solar fuels under mild conditions. However, the rational regulation of product selectivity, especially the directional conversion of CO2 toward either shallow reduction products such as carbon monoxide (CO) or deep reduction products such as methane (CH4), remains a major challenge. In this study, two carboxyl-position isomeric covalent organic frameworks covalent organic framewo