An efficient, one-pot and catalyst-free pathway is reported for the synthesis of novel chromeno[1,6]naphthyridine
derivatives via the multi-component condensation reaction of salicylaldehyde derivatives, malononitrile dimer and active
methylene compounds. All the reactions were carried out in polyethylene glycol-400 as a green solvent at 80 °C. The
reactions had a high atom economy and new products were synthesized with good yields and a simple work-up procedure
with water as the only by-product.