Hierarchical Self-Assembly of Discrete Metal-Organic Supramolecules with Emergent Properties and Functions

Hierarchical self-assembly, wherein simple molecular components undergo multiple, ordered organization steps, underlies the construction of complex functional architectures in biological systems and has inspired advances in artificial supramolecular chemistry. In this context, hierarchically assembled metallosupramolecular architectures (HAMSAs) have emerged as versatile platforms that combine enhanced structural complexity with emergent properties inaccessible to single-step assemblies. This review provides a comprehensive overview of bottom-up hierarchical strategies for constructing discrete metal-organic supramolecular systems. Six representative pathways are delineated based on the dominant interactions driving secondary assembly: coordination-coordination, coordination-metal-metal, coordination-anion induction, coordination-π···π stacking, coordination-dynamic covalent bonding, and coordination-other interactions. Emphasis is placed on elucidating the structure-function relationships underlying hierarchical self-assembly, where structural dynamics, differentiated disassembly/reassembly pathways, and conformational adaptability give rise to higher-order host-guest behaviors, which further evolve into synergistic effects and functional coupling. Through this hierarchical progression from dynamic modularity to emergent multifunctionality, luminescent, catalytic, magnetic, and biochemical functions exemplify how multilevel organization governs complex behaviors. By integrating three decades of developments (1997-2025) with foundational studies, this review aims to establish a conceptual framework for rationally constructing next-generation metallosupramolecular systems with biomimetic complexity and integrated functionality.