It is well-known that low dielectric materials are used as insulating materials, and the incorporation of fluorinated substitutes into polymer is able to decrease its dielectric constant because of small dipole and the low polarizability of the C-F bond. In this study, a novel structure of the fluorinated benzoxazine (F-I benzoxazine) has been synthesized by incorporating the trifluoromethyl groups into the monomer, and its structure has also been characterized by H-1 NMR, F-19 NMR and FT-IR. Further, we have prepared the fluorinated copolybenzoxazine (B-a/F- = 1/1) with substantially reduced dielectric constant at K = 2.36. In addition, this fluorinated copolybenzoxazine possesses high glass transition temperature and high thermal stability, which is suitable for high temperature operation for certain special processes of interlayer dielectrics. (C) 2003 Published by Elsevier Ltd.