Abstract5-chloromethylfurfural (5-CMF) was produced from carbohydrates and lignocelluloses under the catalysis of Lewis acids. The millimole scale-up synthesis of 5-CMF from carbohydrates was successfully performed using metal chlorides or mixed metal chlorides as a catalyst in a heterogeneous system. The process involved the heating of the feedstock in a biphasic hydrochloric acid/organic solvent reactor over several hours. The process was later applied to raw biomass, which gave 5-CMF yields comparable to that of carbohydrates, based on the hexose content. It was found that mixed catalysts consisting of CrCl3 and ZnCl2 played an effective role in the transformation. The 5-CMF can be directly obtained in nearly 80% yield from the fructose under the mixed catalysts heterogeneous system. Bamboo pulp, eucalyptus pulp, and bagasse pulp were also directly converted into 5-CMF under this system at the yield of 32.7%, 36.2%, and 50.1%, respectively.