“…Polymer materials exhibit strong designability of the molecular chain structure, good processing performance, and corrosion resistance. − Polyimides, due to their outstanding high-temperature resistance, dielectric properties, and excellent radiation resistance, have found extensive applications in the microelectronics industry, particularly in large-scale and very-large-scale integrated circuits, as functional materials. − However, traditional polymer materials have low thermal conductivity, which is not conducive to the rapid dissipation of heat energy, thus hindering their practical use as thermal management materials. An effective combination of polymers and highly thermally conductive fillers such as boron nitride (BN), graphene, and silicon carbide (SiC) is considered to be an ideal solution. − In addition, thermally conductive fillers should maintain the processability, lightness, and electrical insulation of the composite as much as possible. − Among them, boron nitride nanosheets (BNNS) show a hexagonal crystal structure similar to graphite and are the promising thermal conductive filler because of its high thermal conductivity, which is the best thermal conductivity among ceramic materials, together with high insulation, high heat resistance, and good mechanical properties. − Considering these advantages of BNNS, it is believed that high thermal conductivity could be obtained by constructing orderly and continuously interconnected BNNS structures in composite materials, so many researchers have improved the thermal conductivity of the material by introducing BNNS . Nevertheless, most strategies to improve thermal conductivity by incorporating thermally conductive fillers will inevitably sacrifice the mechanical property and flexibility. − Especially under high filler loading, it will lead to poor processing ability and severe deterioration of the mechanical properties of composites, which limits their potential applications. , Accordingly, constructing an effective thermal conduction path with a minimum filler content through structural manipulation is extremely critical and also remains a great challenge.…”