This research reports a green and efficient protocol for the one-pot synthesis of dihydro-1H-indeno[1,2-b]pyridines and polysubstituted imidazoles using a recyclable acidic ionic liquid [H-NP]HSO4 (H-NPBS). Non-corrosiveness, safe, low waste, generality, simplicity, easy for separation, short reaction times, high yields and environmentally benign are some of the advantages of this methodology. The [H-NP]HSO4 (H-NPBS) has been effectively recycled for six consecutive cycles without appreciable loss in its activity
