A novel phosphonic acid and triazolyl functionalized poly(ether sulfone) (PES-TriPA) containing simultaneously phosphonic acid and triazolyl side groups is synthesized. The PES-TriPA is prepared by polycondensation of phosphonated bisphenol (PBP) and 3,3'-diethynyl-4,4'-difluorodiphenylsulfone, followed by click reaction to introduce triazolyl groups and hydrolysis to free phosphonic acid groups. Phosphonic acid functionalized poly (ether sulfone) (PES-PA) and triazolyl functionalized poly(ether sulfone) (PES-Tri) are also synthesized for comparison with PES-TriPA. The proton conducting polymers are hot-pressed into proton exchange membranes, and the membrane morphologies, proton conductivities, oxidation and thermal stabilities, water uptakes and methanol permeabilities are characterized. PES-TriPA exhibits more excellent comprehensive properties in comparison with PES-PA and PES-Tri. At 100 degrees C and 90% relative humidity (RH), the proton conductivity of PES-TriPA reaches 113.0 mS cm(-1), in comparison with 55.7 mS cm(-1) for PES-PA and 4.3 mS cm(-1) for PES-Tri. PES-TriPA also shows better oxidation stability with 95.7% weight left after Fenton's test at 80 degrees C for 120 h, while only 68.7% left for PES-PA and 75.7% left for PES-Tri. In addition, PES-TriPA exhibits favorable thermal stability and water uptake compared with PES-PA and PES-Tri. Moreover, the methanol permeability of PES-TriPA is only 0.24 x 10(-8) cm(2) s(-1), which is lower than these of PES-PA and PES-Tri with 0.77 x 10(-8) cm(2) s(-1) and 1.20 x 10(-8) cm(2) s(-1), respectively. These superior characteristics are attributed to the synergetic effect between the phosphonic acid groups and triazolyl groups caused by the intermolecular hydrogen bonding interaction throughout the PES-TriPA acid-base amphoteric polymer.