c-Myc inhibitor15 (Compound A5) is a selective c-Myc inhibitor that disrupts the interaction between c-Myc and Max, leading to c-Myc protein degradation and apoptosis (Apoptosis). It exhibits potent cytotoxic activity with IC50 values of 4.08 μM and 7.86 μM in A549 and NCI–H1299 lung cancer cell lines, respectively. In an allogeneic tumor model, c-Myc inhibitor15 demonstrated outstanding antitumor efficacy, achieving a tumor growth inhibition rate of 76.4% and significantly reducing c-Myc protein expression. This compound shows promise for research related to c-Myc-associated lung cancer.