Glycine betaïne hydrochloride (BHC), a safe acid industrially produced from the largely available glycine betaine isolated from the manufacture of sugar from beet, was used in combination with water to produce sustainable reaction media capable of selectively converting agricultural wastes to furfural and levulinic acid. At the end of the process, BHC can be conveniently recovered and recycled. Under optimized conditions, furfural was produced with 65% and 73% yield from wheat straw and xylan originated from beechwood, respectively. More importantly, by closely controlling the reaction temperature, it was possible to selectively drive the reaction either to xylose, furfural or levulinic acid. This process based on the use of biodegradable and safe BHC opens a sustainable route for the production of valuable fine chemicals from lignocellulosic biomass.