AGX51 is a first-in-class pan-Id (inhibitors of DNA-binding/differentiation proteins) antagonist and degrader. AGX51 inhibits the Id1-E47 interaction, leading to ubiquitin-mediated degradation of Ids, cell growth arrest, and reduces viability. AGX51 inhibits the TNBC cell lines with IC50s of nearly 25 μM. AGX51 can be used for the research of cancer.