© 2022 Elsevier Masson SASIn this study, mechanochemical synthesis (MCS) was performed on the ternary and quaternary B2O3/TiO2/Mg/C system in order to investigate the probable reaction products. As being a high-energy ball milling (HEBM) technique, MCS was conducted on the B2O3–TiO2–Mg, B2O3–Mg–C and B2O3–TiO2–Mg–C powder blends. Various milling times were applied for MCS optimization. Besides, the effect of excess amount of Mg on the MCS process was investigated. Subsequently, a purification step was carried out on the milled powders to remove MgO by-product. The MgO content in the as-synthesized powders was leached out using 6 M HCl solution. Thermodynamic evaluations were made utilizing both the FactSage 7.1 and HSC thermochemical software to predict the reactions and products for each system. The as-synthesized and purified powders were characterized by using X-ray diffractometry (XRD), scanning electron microscopy/energy dispersive spectrometry (SEM/EDS), transmission electron microscopy (TEM), particle size analysis (PSA) and differential scanning calorimetry (DSC) techniques. Pure TiB2, B4C and TiC–TiB2 powders were synthesized from stoichiometric B2O3–TiO2–Mg, B2O3–Mg–C and B2O3–TiO2–Mg–C powder blends after MCS for 4 h, 10 h and 6 h, respectively. High purity TiB2, B4C and TiC–TiB2 powders were obtained with an average particle size of 50.20 nm, 330 nm and 17 nm, respectively.