Green synthesis of 2,2-dimethyl-4-oxo-4,5-dihydropyrano[2,3-d][1,3]dioxine-6-carbonyl)-2,3-dihydrophthalazine-1,4-diones 7 were developed by the reaction of diethylphthalate 1 with ethyl cyanohydrazide 2 to form 3-(1, 4-dioxo-3, 4-dihydrophthalazin-(1H)-yl)-3-oxopropanenitrile 3. Then, 3 reacted with benzaldehydes 4 by Knoevenagel condensation to form chalcones (E)-2-(1,4-dioxo-1,2,3,4-tetrahydrophthalazine-2-carbonyl)-3-phenylacrylonitriles 5. Compound 5 undergo further condensation with meldrum's acid 6 to form 7 with good yields in [DBU][Ac]. Compound 7 could also be synthesized by one-pot four component synthesis with excellent yields with short time.