High mobility thin film transistors (TFTs) based on zinc oxynitride (ZnON) semiconductor were fabricated onto polyethylene-2.6-naphthalate (PEN) substrates. The application of a dual gate structure enhanced the field-effect mobility from 65.8 to 147 cm(2)/ $\text{V}\cdot \text{s}$ , which is generally attributed to the bulk accumulation effect. Dual gate driving also results in improved device stability with respect to bias and illumination stress. This is most likely due to the fact that the bulk channel confines the charge carriers away from the semiconductor-dielectric interfaces, where charge trapping is anticipated. The electrical performance of dual gate devices did not change significantly after 5,000 bending cycles, while the single gate transistors exhibited clear degradation.