In this study, a novel process using ink jet printing with dilute PMMA [poly(methylmethacrylate)] solution to form fine separation banks as confined boundaries for the subsequent depositing poly(3,4–ethylene dioxythiophene) (PEDOT) was proposed. The PEDOT comprised the source and drained electrodes with a gap of several micrometers due to the innate characteristic of the ring edge of ink jetted PMMA. Using this technique, the organic device was designed with a bottom gate and evaporated pentacene as the channel material. The device mobility and on/off ratio were about 3.6×10^-4 and 2×10²/V sec, respectively.