In the present study, a method based on sulfuric acid dehydration of sugar was developed to synthesize a precursor material, which can yield B4C/SiC composites at much lower temperatures compared to traditional carbothermal methods. The precursor material for pure B4C was heat treated at the temperatures between 400 and 1600 degrees C under inert atmosphere. The precursor material for B4C/SiC composites was heat treated only at 1600 degrees C under an inert atmosphere. Then the samples were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results showed that B-C bonds formed as low as 400 degrees C. On the other hand, crystallized B4C and B4C/SiC composites can be obtained at the heat treatment temperatures between 1400 and 1600 degrees C.