We have synthesized a thermally curable polymeric gate insulator (TFVOB-PVP) through the modification of the well-known poly(4-vinylphenol) (PVP) polymer using a 4-(1,2,2-trifluorovinyloxy) benzoyl (TFVOB) chloride. The thermal cross-linking of TFVOB-PVP was conducted and produced the cross-linked TFVOB-PVP with the perfluorocyclobutane (PFCB) structure. The PFCB structure was formed by the radical mediated thermal cycloaddition of trifluorovinyl ether group of TFVOB. The cross-linked TFVOB-PVP showed good thermal stability up to 423 degrees C with only 5% weight loss and excellent chemical resistance to common organic solvents. The pentacene thin-film transistor (TFT) with the cross-linked TFVOB-PVP as a gate dielectric exhibited a field effect mobility of 0.14cm(2)/Vs with almost no hysteresis during the TFT operation.