A　novel　high-performance　epoxy　resin　diphenyldi　(9,9-Di-(4-(2,3-epoxypropoxy)　phenyl)-4,5-diazafluorenoxysilane)　(DEPFS)　containing　the　diazafluorene　and　silicon　group　was　synthesized　by　the　nucleophilic　substitution　for　the　first　time　and　added　to　bisphenol　A　epoxy　resin　(E-51)　to　form　a　thermoset　blend.　We　observed　that　the　incorporation　of　DEPFS　remarkably　enhanced　the　flame　retardancy　and　thermal　properties　of　E-51.　The　cured　E-51-30%　DEPFS　thermoset　exhibited　a　glass　transition　temperature　of　187　°C　and　a　limiting　oxygen　index　of　30.1%,　much　higher　than　153　°C　and　22.6%　for　those　of　pristine　E-51　thermoset,　respectively.　In　addition,　the　incorporation　of　DEPFS　has　dual　enhancement　effects　on　the　toughness　and　tensile　strength　of　E-51.　This　study　provides　an　effective　means　to　prepare　a　high-performance　epoxy　resins　and　proposes　flame　retardancy　and　simultaneous　reinforcing　and　toughening　mechanism.　It　was　found　that　the　DEPFS　with　diverse　performance　has　allowed　an　increasing　number　of　versatile　industrial　application　such　as　microelectronics,　electronics,　aerospace　and　so　on.　©　2019　Elsevier　Ltd