Abstract A novel series of 4-pyrazolyl-1, 8-naphthalimide derivatives have been designed and facilely synthesized. For anticancer activity in vitro, most of the compounds were found to be more toxic against human mammary cancer cells (MCF-7) than human cervical carcinoma cells (Hela) and human lung cancer cells (A549). Compounds 4i, 4h, 4b and 4a showed improved cytotoxic activity against MCF-7 cells over amonafide, in particular ...