Molybdate sulfuric acid (MSA) has been found as an efficient and reusable solid acid catalyst for the synthesis of new 2, 3, 4, 5-tetrasubstituted pyrroles via a novel [2+ 2+ 1] strategy. Thus, one-pot three-component reaction of benzoin derivatives, 1, 3-dicarbonyls, and ammonium acetate afforded the desired products in high yield under solvent-free conditions.