Switchgrass biomass samples collected at three different stages of maturity were seen degrading into reducing sugars and glucose when exposed to 1-(alkylsulfonic)-3-methylimidazolium Brönsted acidic ionic liquids under thermal and microwave conditions. The highest reducing sugar (58. 1 ± 2. 1 %) and glucose (15. 3 ± 0. 5 %) yields were obtained for switchgrass samples dissolved in 1-(butylsulfonic)-3-methylimidazolium chloride ionic liquid by heating at 70 °C for 1 h followed by treatment with 0. 22 g water/g switchgrass and then heating at 70 °C for 1 h for the hydrolysis of polysaccharides. The samples treated under microwave conditions produced relatively lower yields of reducing sugar (22. 0 ± 1. 5-37. 2 ± 1. 8 %) and glucose (8. 0 ± 0. 2-12. 8 ± 0. 4 %) yields, compared to heat-treated samples. © 2012 Springer Science+Business Media New York.