In this work, an organic thin film transistor (OTFT) with bottom gate - bottom contact (BGBC) structure on glass, with organic dielectric and semiconductor, was fabricated to use it as a gas sensor in the detection of isoborneol (IB) in water. No BGBC OTFTs fabricated on glass substrate with poly(4-vinylphenol) (PVP) dielectric and poly(2,5-bis(3-tetradecyl-thiophen-2-yl)thieno[3,2-b]thiophene) (PBTTT-C14) semiconductor as a gas sensor for IB detection were found in the literature consulted. Conjugated polymers, such as the polythiophene derivative PBTTT-C14, exhibit semiconducting electrical properties. Due to the dimensions of the main chain of this material and the compact and organized stacking of it when in a film, it is possible to obtain structures known as terraces. The presence of these structures entails a better electrical performance of the devices fabricated from this organic semiconductor. Solutions of the cross-linked PVP organic dielectric and the PBTTT-C14 organic semiconductor were deposited by spin coating. A system integrating these sensors could be useful in real-time monitoring of water quality.