We report on the fabrication and characterization of pentacene based thin-film transistors (TFTs) with low- poly-4-vinylphenol (PVP)/high- yttrium oxide bilayer gate dielectrics of various thickness combinations, for the thin-PVP layers (45, 70, and ) and for the thin (50 and ). Neither nor thin-PVP single layer film alone can properly function as a dielectric layer due to their very high leakage current. However, our bilayer films of six different thickness combinations (among which the thinnest was while the thickest was ) all exhibited quite a good dielectric strength of , based on our maximum leakage current standard of . All pentacene TFTs with the bilayer gate dielectric films successfully demonstrated good TFT characteristics at an operating voltage less than . In particular, two of our devices studied here with the bilayer combinations (45 nm thin PVP on 50 nm and 100 nm thick ) exhibited good device performance with field effect mobilities (1.74 and ) and an on/off current ratio of . We also demonstrate a resistance-load inverter operating below with a load resistance of connected to our pentacene TFT with a PVP layer.