A method for lignocellulose conversion to sugar with improvements in yield and rate of sugar production has been developed by using ionic liquid pretreatment. This new pretreatment strategy substantially improves the efficiency (in terms of yield and reaction rates) of saccharification of lignocellulosic biomass. Cellulose and hemicellulose, when hydrolyzed into their sugars, can be converted into ethanol fuel through well established fermentation technologies. These sugars also form the feedstocks for production of variety of chemicals and polymers. The complex structure of biomass requires proper pretreatment to enable efficient saccharification of cellulose and hemicellulose components to their constituent sugars. Current pretreatment approaches suffer from slow reaction rates of cellulose hydrolysis (by using the enzyme cellulase) and low yields.