Strategic engineering of structural complexity in metal–organic frameworks

Structural complexity in metal–organic frameworks (MOFs) can be engineered through controlled defect creation, multivariate linker integration, and hierarchical pore construction. Spatially distributed metal nodes and organic linkers within multivariate MOFs enable synergistic interactions and multifunctional site generation. Defect engineering unlocks mesoporosity and introduces chemically active sites, supporting advanced applications in catalysis, drug delivery, and sensing. The review provides rational design strategies for modulating structural complexity and tuning pore environments across multiple length scales. Combining diverse complexity strategies in a single MOF offers a powerful route to designing multifunctional, multiscale materials. Structural complexity in nature emerges from simple building blocks, yielding robust and multifunctional materials. In response to the growing demand for programmable, time-sensitive materials, metal–organic frameworks (MOFs) have emerged as ideal platforms for engineering complexity across multiple scales and environments. Their modularity allows the incorporation of multivariate metal nodes and organic linkers based on their topology, creating tailored pore environments and spatially varied functionalities. This review categorizes MOFs into three strategic approaches to structural complexity: metal node defect engineering, multivariate linker design, and hierarchical pore engineering. These approaches are highlighted for their broad application potential and offer valuable insights for the future design of complex, functional materials. Structural complexity in nature emerges from simple building blocks, yielding robust and multifunctional materials. In response to the growing demand for programmable, time-sensitive materials, metal–organic frameworks (MOFs) have emerged as ideal platforms for engineering complexity across multiple scales and environments. Their modularity allows the incorporation of multivariate metal nodes and organic linkers based on their topology, creating tailored pore environments and spatially varied functionalities. This review categorizes MOFs into three strategic approaches to structural complexity: metal node defect engineering, multivariate linker design, and hierarchical pore engineering. These approaches are highlighted for their broad application potential and offer valuable insights for the future design of complex, functional materials.