The development of anhydrous proton conducting membrane is important for the operation of polymer electrolyte membrane fuel cell (PEMFC) at intermediate temperature (100-200 degrees C). In this study, we have investigated the acid-base hybrid materials by mixing of strong phosphonic acid polymer of poly(vinylphosphonic acid) (PVPA) with the high proton-exchange capacity and organic base of heterocycle, such as imidazole (Im), pyrazole (Py), or 1-methylimidazole (Melm). As a result, PVPA-heterocycle composite material showed the high proton conductivity of approximately 10(-3) S cm(-1) at 150 degrees C under anhydrous condition. In particular, PVPA-89 mol% Im composite material showed the highest proton conductivity of 7 X 10(-3) S cm(-1) at 150 degrees C under anhydrous condition. Additionally, the fuel cell test of PVPA-89 mol% Im composite material using a dry H-2/O-2 showed the power density of approximately 10 mW cm(-2) at 80 degrees C under anhydrous conditions. These acid-base anhydrous proton conducting materials without the existence of water molecules might be possibly used for a polymer electrolyte membrane at intermediate temperature operations under anhydrous or extremely low humidity conditions. (c) 2005 Elsevier Ltd. All rights reserved.