Pyrimidopyrimidine derivatives, organic thin film transistors using pyrimidopyrimidine derivatives and method for fabricating the same are provided. Pyrimidopyrimidine derivative structures, along with example syntheses, are provided. The pyrimidopyrimidine derivatives may be pyrimidopyrimidine oligothiophene derivatives in which an oligothiophene having p-type semiconductor characteristics may be bonded to a pyrimidopyrimidine having n-type semiconductor characteristics positioned substantially in the center of the molecules, thereby simultaneously exhibiting both p-type and n-type semiconductor characteristics. The pyrimidopyrimidine derivatives may be spin-coated at room, or ambient, temperature when applied to the fabrication of an electronic device, for example, organic thin film transistors. Organic thin film transistors using the pyrimidopyrimidine derivatives may provide higher charge carrier mobility and/or lower off-state leakage current.