Conjugated fullerene C60 networks: From bonding motifs to multifunctional properties

Conjugated fullerene C60 networks, formed through inter-cage covalent bonding, constitute a versatile carbon platform in which bonding configuration, topology, and dimensionality can be engineered to realize a broad spectrum of multifunctional properties. This review surveys recent progress in two-dimensional covalently bonded, conjugated C60 networks, with an emphasis on synthetic strategies that enable structurally well-defined phases. We establish a synthesis–structure–property framework that links synthetic routes to inter-cage bonding motifs, network topology, and the resulting electronic, mechanical, and thermal transport responses. Beyond summarizing key advances, we critically assess the origins of the substantial scatter in reported properties, tracing it to methodological variations in simulations, particularly the choice of electronic-structure approximations and interatomic potentials as well as the limited availability of reliable experimental data. On this basis, we identify transferable structure–property relationships to guide future materials design. Outstanding challenges are discussed, including precise control over bonding topology, fabrication of well-defined specimens for reproducible and orientation-dependent measurements, and the establishment of quantitative experimental benchmarks. Finally, we outline prospective pathways toward property optimization and validation in device-relevant contexts.