abstract-a novel and efficient method has been developed for the synthesis of pyrano[3,2-c]quinoline-2,5-dione derivatives by the convenient ultrasound-mediated condensation of 4-hydroxyquinolin-2-one with meldrum’s acid and aldehydes in the presence of a catalytic amount of [hmim]hso4 as a green, efficient and reusable acidic ionic liquid medium. the stability of the ionic liquid during the re...