We report a novel proof-of-concept FET design (CoreFET) based on a thin wire, which can be fabricated without any micromanufacturing processes. Zinc oxide (ZnO) and Poly(3-hexylthiophene) (P3HT) were used to develop thin film CoreFETs, with the central core of a wire acting as a gate terminal. The design may be used for multiple electronic and optoelectronic devices, and the unique wire shape renders it favorable for specific applications, such as chemical and biological sensing.