Constructing Lanthanide‐Based Single‐Molecule Magnets Assemblies by Octacyanometallate Bridge^†

Comprehensive Summary In recent years, significant breakthroughs in the enhancement of energy barriers ( U eff ) and blocking temperatures ( T B ) of lanthanide single‐ion magnets (Ln III ‐SIMs) have made high‐density information storage and high‐speed data processing at the molecular level increasingly feasible. As research on Ln III ‐SIMs deepens, scholars are reevaluating polynuclear complexes to enhance their multifunctionality. Cyano bridge has emerged as a commonly used strategy for constructing polynuclear complexes. Notably, Ln III ‐SMMs based on octacyanometallates exhibit diverse topological structures and magnetic interactions, providing new perspectives for developing ordered supramolecular assemblies and high‐dimensional frameworks. Our review provides an exhaustive exploration of octacyanometallate‐bridged {Ln III M IV/V } SMMs (M = Mo, W, and Re). We first systematically analyze existing knowledge of Ln III ‐SMM bridging systems to establish a foundation for understanding their structure‐property relationship. Subsequently, we categorize these complexes based on their ancillary ligands, offering insights into their functionality and the role of cyano bridges in mediating magnetic interactions between metal ions. Finally, we discuss potential strategies aimed at optimizing structures to further enhance SMM performance and functionality. We anticipate that a deeper comprehension of the magnetic characteristics of cyano‐bridged lanthanide complexes will foster the development of functional and application‐driven cyano‐bridged Ln III ‐based molecular systems. Key Scientists