Abstract The kinetics of hydrolysis of 1, 8-N-butyl-naphthalimide (1, 8-NBN) to 1, 8-N-butyl- naphthalamide (1, 8-NBAmide) and of 2, 3-N-butyl-naphthalimide (2, 3-NBN) to 2, 3-N-butyl- naphthalamide (2, 3-NBAmide), as well as the formation of the respective anhydrides from the amides were investigated in a wide acidity range. 1, 8-NBN equilibrates with 1, 8- NBAmide in mild alkali. Under the same conditions 2, 3-NBN quantitatively yields 2, 3- ...