The present study aims to develop a thermoluminescence (TL) material for dosimeter that might potentially surpass the performance of passive dosimeters that are currently available. The study focuses on the essential TL characteristics of biochar that is rich in carbon. The main thermoluminescence (TL) dosimetric properties of commercially available biochar under exposure to X-ray photon beams from Linac at doses ranging from 2 Gy to 20 Gy have been examined. These properties include dose response, sensitivity, TL glow curve, energy dependency, and fading. It has been demonstrated that the biochar provides an excellent linear response in the dose range under study and sensitive at lower dose. The biochar sample demonstrated great reproducibility, with a standard variation of less than 3%. Furthermore, a fading study was conducted and a minimum rate of fading for ambient light and dark room circumstances was discovered. The dose-dependent microstructural degradation of biochar is confirmed by SEM/EDX analysis. The structural changes caused by the radiation doses are being monitored using Raman spectra and X-ray diffraction (XRD). The kinetic parameters analysis also confirms the structural alteration brought by photon irradiation. As a result, biochar demonstrates the significant potential to be used in dosimetric applications.