In a typical procedure, suspend 1.0 g (2.9 mmol, 1.0 eq) of dimaleimideacid222 (3a) in dichloromethane (15 mL), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC, 1.22 g, 6.4 mmol, 2.2 eq) were added and the resulting mixture was stirred at room temperature and stirred for 10-15 minutes to form clear solution. The reaction mixture was then poured into 10% aqueous sodium bicarbonate solution (25 mL) and stirred for 10 min. The aqueous layer was extracted with dichloromethane (2 x 25 mL), and the combined organic layers were washed with 10% aqueous sodium bicarbonate solution (25 mL), water (25 mL), and brine (25 mL). The organic layer was then dried over anhydrous MgSO4 and filtered. Removal of volatiles using a rotary evaporator gave a product , 3b as white solid (0.87 g, 97%). To generalize this methodology, we treated several maleamic acid derivative with EDC furnished exclusively the corresponding desired N-arylisomaleimides in 90-98% yields. The phthalanilic acid also gave the corresponding N-alkyl-iso phthalimide in 90-95% yields indicating that the present dehydration condition works equally well in prolong period.