Structure-activity relationships of novel substituted naphthalene diimides as anticancer agents

► Different groups were inserted on the side rings of symmetric naphthalene diimides. ► Significant antitumor activity with pIC50 values ranging from 6 to 7. ► The most potent compound 20 was characterized by a 2,3,4-trimethoxy substituent. ► It inhibited Taq polymerase, ERKs phosphorylation, and downregulated ERK 2 protein.