The acidic ionic liquid, 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate [MimC4SO4H]HSO4 catalyzed two-component condensation reaction of phenacyl bromide and o-phenylenediamine to afford corresponding quinoxaline derivatives. The inexpensive and non-toxic ionic liquids can be reused several times without any perceptible loss of their activities.