Magnesium-1,4-benzenedicarboxylic acid (Mg-TPA) and magnesium-1,3,5-benzene tricarboxylic acid (Mg-TMA) MOFs were synthesized and successfully incorporated in a poly (ethylene oxide) (PEO) matrix as filler for different proportions of LiN(CF3SO2)(2) (LiTFSI) as salt. The membranes prepared were thermally stable up to 360 degrees C. The ionic conductivity of the polymer electrolytes was enhanced upon addition of MOF and a maximum conductivity of 7.02 x 10(-4) S cm(-1) was achieved for CPE containing 10 wt % of Mg-TPA as filler. The interfacial properties of the CPEs with lithium metal anode were analysed by compatibility, Fourier transform infrared (FT-IR) and XPS analyses. Li/NCPE/Li symmetric cells were assembled and the dendrite growth was also studied. The lithium transference numbers (t (+)(Li)) was measured as 0.58 and 0.52 for the CPE containing Mg-TPA and Mg-TMA, respectively which is appreciable for battery applications. The influence of different organic ligands on the electrochemical and interfacial properties of solid polymer electrolytes was investigated and discussed. (C) 2019 Elsevier Ltd. All rights reserved.