A new chemically modified graphene was prepared using carboxylated graphene oxide (GO) and fluorinated poly(hydroxyamide) (6FPHA), the latter is the precursor of fluorinated poly(benzobisoxazole) (6FPBO). The results showed that, unlike common GO, which can only be dispersed in water under neutral or basic conditions, the RGO–6FPBO (reduced graphene oxide–6FPBO) could be stably dispersed in Lewis acids. The RGO–6FPBO–poly(benzobisoxazole) (PBO) composite was achieved by simple solution blending of RGO–6FPBO and PBO in methanesulfonic acid. The obtained RGO–6FPBO–PBO composite films exhibited a dramatic increase in electrical conductivity, by 8 orders of magnitude at the RGO–6FPBO content of 4 wt%, without significantly sacrificing optical transparency. When the content of RGO–6FPBO was higher than 4 wt%, the dielectric constant of the composite film also increased remarkably. The mechanical properties and thermal stability of the composite were also improved by the incorporation of RGO–6FPBO.