An efficient protocol for synthesis of novel polyheterocyclic chromeno pyrimido[1,2-b]indazolone derivatives using [Et3NH][HSO4] as a reusable catalyst under solvent-free conditions

•Chromeno pyrimido[1,2-b]indazolone was synthesized from one-pot reactions.•The reactions are undergoing in solvent-free conditions.•Broad substrate scope and good functional compatibility.•Excellent yield and column chromatography-free are the main advantage of this method.