The journey for sustainable solutions in the environment to create safe, cheap and assessable materials in society requires the use of more plant-based natural fibres in the industry. In this work, the acid hydrolysis process was adopted to isolate organosolv-microcrystalline cellulose (MCC) from oil palm fronds (OPF). Complementary analyses such as cross polarisation/magic angle spinning nuclear magnetic resonance (CP/ MAS 13C NMR), Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), gel permeation chromatography (GPC), and X-ray diffraction (XRD) revealed extracted MCC bear a resemblance to commercial-MCC. Polymer solution casting technique was adopted to prepare different ratios of MCC-polylactic acid (PLA)-lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) solid polymer electrolytes and electrical conductivities of polymer electrolyte films were investigated through electrochemical impedance spectroscopy (EIS). BO5 (organosolv-MCC-PLA-20 wt% LiTFSI) showed the maximum ionic conductivity of 1.25 x 10-5 S cm-1, while 5 wt% 1-butyl-3-methylimidazolium chloride (BMIMCl) ionic liquid added revealed a positive effect of BMIMCl on the ionic conductivity of the polymer electrolyte yielding a higher conductivity of 2.3 x 10-5 S cm-1.