Proton-exchange membranes (PEMs) as separators have [GRAPHIC] important, technological applications in electrochemical devices, including fuel cells; electrochemical sensors, electrochemical reactors, and electrochromic displays. The composite membrane of a proton conducting metal-organic framework (MOF) and an organic polymer combines the unique physical and chemical nature of the polymer and the high proton conductivity of the MOP, bringing together the best of both components to potentially fabricate high-performance PEMs, In this study, we have investigated the proton-transpot nature of a zirconium(IV) MOF, MOF-808 (1). This superior-water-stability IMF shows striking proton conductivity with sigma = 7.58 X 10-3 S.cm(-1) at 315 K and 99% relative humidity. The composite membranes, of 1 and poly(vinylidene fluoride) (PVIDF) have further been fabricated and are labeled as 1@PyDF-X, where Xrepresents the mass percentage of 1 (as X%) in l@PVDF-X and X = 10-55%. The composite membranes exhibit good mechanical features and durability for practical application and a considerable proton conchictivity of 1.36 x 10(-4) S.cm(-1) in deionized water at 338 K as well. Thus, the composite membranes show promising applications as alternative :PEMs in diverse electrochemical devices.