The CO(2/)light gases separation of azide crosslinked poly(4-methyl-1-pentyne) (PMP), morphology and physical stabilities of membranes were studied. The gases permeability and membrane fractional free volume (FFV) both decreased as the crosslinking percent increased. The CO2/CH4 and CO2/N-2 selectivities were increased from 11.2 to 15.2 and 16.4 to 20.5; respectively upon crosslinking. The gases permeability was increased by adding CuBTC particles into PMP matrix. CO2 showed the superior permeability compared to other gases upon adding CuBTC due to the high affinity to filler. Selectivity for the gas pairs CO2/CH4, CO2/N-2 and CO2/H-2 raised for all MMMs as CuBTC loading increased from 5 to 20 wt.%. The quality of filler dispersion in polymer was evaluated by means of scanning electron microscopy (SEM) and the outcomes proved the appropriate dispersion of MOF particles within the PMP matrix. Moreover, the thermal stability of membrane enhanced upon crosslinking and particles inclusion. The physical aging of neat PMP, crosslinked PMP and MMMs was studied through long term CO2 permeation and the results showed that crosslinking was the effective method to maintain both permeability and selectivity of PMP and MMMs over the time. (C) 2018 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.