HLDA-212 (Compound 43) is a bifunctional small molecule designed to target HaloTag-tagged protein (target protein, TP) and Aurora kinase A/B (AURKA/B, effector protein, EP). By binding TP and EP, it forms a stable ternary complex (TP:RIPTAC:EP) that inhibits the cell survival functions of EP, inducing apoptosis in cancer cells expressing TP. In 293_HFL cells, HLDA-212 demonstrates antiproliferative activity with a GI50 of 0.011 μM. This compound holds promise for treating cancers with high TP expression, such as prostate cancer and hematological malignancies.