As a new type of filler for mixed matrix membranes (MMMs), metal-organic frameworks (MOB) have received increasing attention. As a kind of MOFs, [CU2(bdc)(2)(bpy)](n), is successfully synthesized in this work and characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), wide angle X-ray diffraction (WAXRD), thermogravimetric analysis (TGA) and adsorption isotherms. [CU2(bdc)(2)(bpy)](n), is found to preferentially adsorb methanol (MeOH) over methyl ter-butyl ether (MTBE). For this reason, the [Cu-2(bdc)(2)(bpy)](n) is incorporated into sulfonatecl polyarylethersulfone with cardo (SPES-C) to form [CU2(bdc)(2)(bpy)](n)/SPES-C MMMs for the separation of MeOH/MTBE mixtures. Both the sorption selectivity and the diffusion selectivity are found to increase with the addition of [CU2(bdc)(2)(bpy)](n) leading to an increase in the separation factor. With increasing [CU2(bdc)(2)(bpy)](n) loading from 5 to 20 wt%, the flux increased up to 0288 kg m 2 h at 20 wt% loading. A threshold of [CU2(bdc)(2)(bpy)](n) loading is approximately 20 wt% where the flux remains almost constant regardless of further increasing the [CU2(bdc)(2)(bpy)](n), content. This work demonstrates an improved performance of the [CU2(bdc)(2)(bpy)](n)/SPES-C MMMs for the separation of MeOH/MTBE mixtures. (c) 2013 Elsevier B.V. All rights reserved