Provided are an organic semiconductor compound using thiazole, and an organic thin film transistor having an organic semiconductor layer formed of the organic semiconductor compound using thiazole. The novel organic semiconductor compound including thiazole has liquid crystallinity and excellent thermal stability, and thus is provided to form an organic semiconductor layer in the organic thin film transistor. To this end, a silicon oxide layer is formed on a silicon substrate, and an organic semiconductor layer including thiazole is formed on the silicon oxide layer. In addition, source and drain electrodes are formed on both edge portions of the organic semiconductor layer. The organic thin film transistor using the organic semiconductor layer has an improved on/off ratio and excellent thermal stability. Also, a solution process can be applied in its manufacture.