Designer <i>π</i> -magnetism in magnetic graphene nanostructures: advances and future perspectives

Abstract Magnetic graphene nanostructures (MGNs) represent a rapidly advancing frontier in molecular quantum materials, distinguished by π-magnetism that arises from the topological design of their π-electron networks. The π-magnetism and correlated quantum phases in these systems can be precisely engineered through deliberate control of molecular topology, sublattice symmetry, and electron correlation, transforming low-dimensional carbon-based architectures into versatile model platforms for exploring exotic quantum phenomena. Recent advances in on-surface synthesis have further propelled this field by enabling atomically precise fabrication of MGNs and fine control over their electronic and magnetic properties. Complementing these synthetic advances, progress in low-temperature scanning probe microscopy now affords unprecedented capability to characterize individual π-spins, exchange coupling, and correlated ground states at the single-molecule level. Together, these developments establish a robust foundation for exploring long-lived spin coherence, tunable quantum entanglement, and spin-based logic operations in carbon-based systems. This review highlights recent conceptual and methodological advances, emphasizing how rational molecular design, atomically precise synthesis, and state-of-the-art characterization techniques collectively advance the understanding and realization of π-magnetism in MGNs. Remaining challenges, including stabilizing chemically reactive open-shell structures, mitigating substrate-induced hybridization, and integrating molecular magnets into functional device architectures, are also discussed. Continued progress in this field will reshape our perspective on designing novel forms of magnetism in conjugated organic materials and open new pathways toward scalable molecular spintronics and quantum technologies.