Metal-organic frameworks based on macrocycles: from design to function.

Metal-organic frameworks (MOFs) built from macrocyclic building blocks stand at the intersection of two Nobel-Prize-recognized traditions. Within such lattices, the framework amplifies individual molecular events into bulk material properties through periodic replication and geometric control allowing for recognition, gating, or catalytic specificity that conventional linkers struggle to bestow. The solid-state host-guest behaviour of these hybrid materials diverges from their homogeneous counterparts in solution. The lattice locks cavity conformations to sharpen selectivity, fixes orientations to enable cooperative multisite binding, and combines discrete recognition events with collective responses in conductivity, luminescence, or mass transport. This interplay has already led to macrocyclic MOFs whose performance surpasses that of both parent components. Despite rapid progress, the field still lacks a systematic way of relating macrocyclic properties to material function. Conceptualizing and realizing the full potential of these materials therefore demands a coherent understanding of how macrocycle characteristics dictate reticular compatibility, how synthetic mechanisms govern cavity accessibility, and how these aspects jointly determine function. This review develops that integrated understanding in stages: the physicochemical attributes that matter for the material's reticular nature, the synthetic logic that weaves macrocycles into periodic frameworks, and the emergent performance these architectures deliver. It concludes by outlining the frontiers where macrocyclic MOFs may transition from laboratory proof-of-concept to engineered technology.