Polymer-based　dielectrics　with　high　thermal　conductivity　and　superb　dielectric　properties　hold　great　promising　for　advanced　electronic　packaging　and　thermal　management　application.　However,　integrating　these　properties　into　a　single　material　remains　challenging　due　to　their　mutually　exclusive　physical　connotations.　Here,　an　ideal　dielectric　thermally　conductive　epoxy　composite　is　successfully　prepared　by　incorporating　multiscale　hybrid　fillers　of　boron　nitride　microsphere　(BNMS)　and　silicon　dioxide　coated　silicon　carbide　nanoparticles　(SiC@SiO2).　In　the　resultant　composites,　the　microscale　BNMS　serve　as　the　principal　building　blocks　to　establish　the　thermally　conductive　network,　while　the　nanoscale　SiC@SiO2　as　bridges　to　optimize　the　heat　transfer　and　suppress　the　interfacial　phonon　scattering.　In　addition,　the　special　core–shell　nanoarchitecture　of　SiC@SiO2　can　significantly　impede　the　leakage　current　and　generate　a　great　deal　of　minicapacitors　in　the　composites.　Consequently,　favorable　thermal　conductivity　(0.76　W/mK)　and　dielectric　constant　(∼8.19)　are　simultaneously　achieved　in　the　BNMS/SiC@SiO2/Epoxy　composites　without　compromising　the　dielectric　loss　(∼0.022).　The　strategy　described　in　this　study　provides　important　insights　into　the　design　of　high-performance　dielectric　composites　by　capitalizing　on　the　merits　of　different　particles.　©　2022　Elsevier　Inc.