Highly Efficient Construction and in Situ Post‐Assembly Modification of Multifunctional Metal–Organic Cages in Microdroplets

Abstract Confined microenvironments provide a powerful platform for guiding supramolecular self‐assembly, analogous to intracellular environments that drive key biological processes. Nevertheless, the construction and post‐assembly modification of multifunctional metal–organic cages (MOCs) within microdroplets remains a significant challenge. Here, we present a microdroplet‐based strategy for the rapid and efficient synthesis of structurally diverse tetrahedral MOCs, incorporating functionalities such as aggregation‐induced emission and photosensitization. Compared with batch reactors, reactions in microdroplets led to dramatically accelerated self‐assembly. More importantly, we report the first example of post‐assembly functionalization of MOCs within microdroplets, achieved through azide–cyclooctyne click chemistry, enabling the incorporation of twelve BODIPY chromophores to generate multifunctional cages integrating both photosensitizing and fluorescence functionalities. The confined droplet milieu not only facilitated the self‐assembly but also enhanced the subsequent modification processes. The functionalized MOCs demonstrated markedly enhanced photocatalytic activity within microdroplets, achieving turnover frequencies up to forty times higher than those obtained in batch reactors in the synthesis of the pharmaceutically relevant quinone juglone. Collectively, this study establishes microdroplet reactors as powerful biomimetic platforms for the rapid and precise construction, functionalization, and application of supramolecular architectures.