Organic thin film transistors (OTFTs) were fabricated on polyethersulphone substrate using 6,13-bis(triisopropylsilylethynyl) (TIPS) pentacene as an active layer. and cross-linked poly-4-vinylphenol (PVP) as a gate dielectric. Prior to adoption of PVP as a gate dielectric, the PVP print condition was optimized using a metal-insulator-metal structure and making a comparison with spin coated devices in terms of the leakage current, breakdown voltage, and dielectric constant. Then, OTFTs were fabricated with an optimized PVP gate dielectric and a TIPS pentacene active layer using an ink jet printer. The electrical properties such as the field effect mobility, I-on/I-off ratio, and threshold voltage had values of 0.055 cm(2)/V s, 10(3), and -2.6 V, respectively. The smaller I-on/I-off ratio can be attributed to the smaller coverage of the TIPS pentacene layer due to the plateletlike crystalline structures. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3358162]