A novel thermosetting resin based on vinylic end groups was prepared and its network formation investigated. 2,2-Bis(4-vinylbenzyloxyphenyl)hexafluoropropane was prepared by the condensation of vinylbenzyl chloride with Bisphenol-AF in the presence of K2CO3. This distyrenic monomer was cured thermally to produce a highly crosslinked network with <0.5% sol fraction. The networks prepared by this reactive monomer were brittle. However, their fracture toughness could be modified with the incorporation of vinylbenzyl end-capped perfluoroalkylene aryl ether oligomers. The thermoplastic component phase separated into discrete composite particles in the continuous network phase. The thermoplastic modified network showed improved fracture toughness without sacrificing the modulus or good dielectric characteristics.