Metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), featuring porous crystalline materials, have attracted tremendous attention for various applications due to their periodic and well-defined structures, high surface area, and tunable pore architectures. In particular, the facile modification of MOFs and COFs enables their intermesh into MOF/COF hybrids to enhance performance and/or extend scope toward diverse applications. In this review, we provide an overview of significant progress in the design and synthesis of MOF/COF hybrids, including MOF@COF, COF@MOF, MOF + COF, C-MOF, and COF-in-MOF, and their various applications in catalysis, gas adsorption, sensing, energy storage, and photodynamic therapy. The challenges and prospects of the construction of MOF/COF hybrids for various applications are also briefly discussed. Display omitted The chemistry of metal-organic frameworks (MOFs) and covalent organic frameworks (COFs), collectively referred to as reticular chemistry, has become one of the fastest growing fields of chemistry and materials science. As two important pillars in reticular chemistry, MOFs and COFs have developed in parallel along their respective trajectories for around 2–3 decades, resulting in >80,000 MOFs with >2,000 topologies and >500 COFs with >18 topologies being reported. The integration of structures and functions of these MOFs and COFs will greatly enrich their structures and properties and expand their applications. In addition, the results of integration may also in turn enlighten and promote the development of single MOFs and/or COFs. This review presents an overview of significant progress in the design, synthesis, and applications of MOF/COF hybrid materials. Moreover, the future direction of the nascent field is pointed out. The structure and function integration of MOFs and COFs will greatly enrich their structures and properties and expand their applications. This review presents an overview of significant progress in the design, synthesis, and applications of MOF/COF hybrid materials. In addition, the challenges and prospects of the nascent field are briefly discussed.