We report here on the design, synthesis, processing, and dielectric properties of novel crosslinked inorganic/organic hybrid blend (CHB) dielectric films which enable low-voltage organic thin-film transistor (OTFT) operation. CHB thin films (20-43 nm thick) are readily fabricated by spin-coating a zirconium chloride precursor plus an alpha,omega-disilylalkane cross-linker solution in ambient conditions, followed by curing at low temperatures (similar to 150 degrees C). The very smooth CHB dielectrics exhibit excellent insulating properties (leakage current densities similar to 10(-7) A/cm(2)), tunable capacitance (95-365 nF/cm(2)), and high dielectric constants (5.0-10.2). OTFTs fabricated with pentacene as the organic semiconductor function well at low voltages (<-4.0 V). The morphologies and microstructures of representative semiconductor films grown on CHB dielectrics prepared with incrementally varied compositions and processing conditions are investigated and shown to correlate closely with the OTFT response.