Membrane-based separation is a promising alternative to conventional processes such as cryogenic distillation and/or adsorption based separation. Among the existing membranes for gas separation, polymeric membranes and inorganic membranes have been immensely studied, but each type has its own pros and cons. Therefore, current situation demands the development of mixed matrix membranes (MMMs) by incorporating molecular sieve fillers into the polymer matrix, which provides a decent strategy to combine the merits of each material and fabricate novel hybrid membranes with superior gas separation performance. Metal-organic frameworks (MOFs) have been proposed as novel molecular sieve fillers owing to their unique pore structure and chemical variability. MMMs fabricated using MOFs fillers was supposed to outperform other porous fillers, but due to the limitation in separation performance of the filler within and challenges concerning the compatibility between MOF filler and polymer interface structure, only a small fraction of the works reported both improved permeability and selectivity simultaneously. In this presentation, we will show our research focused on enhancing the compatibility of the MOF filler and polymer matrix by judiciously modifying the MOF’s surface chemistry, and exploring how morphology, particle size and particle distribution drastically influence gas separation performance.