All-polymer capacitors have been fabricated only by the inkjet printing technique. A conductive polymer, poly(3,4-ethylenedioxythiophene), has been employed as the electrode material of the capacitor. A precursor-route polyimide was applied as the insulator of the device. The fabrication process of the inkjet printed all-polymer capacitor has been demonstrated. The electrical characteristics of the polymer capacitor, analogous to that of the common parallel plate capacitor, are discussed in detail. The all-polymer capacitor has been applied to the polymer RC filter circuits. The characteristics of the inkjet printed polymer RC filter are also demonstrated. (C) 2003 Elsevier Science Ltd. All rights reserved.