IMPDHII/HDAC1-IN-1 (Compound C12) is an orally active dual inhibitor targeting IMPDHII and HDAC1, with IC50 values of 84.69 nM and 81.75 nM, respectively. It exhibits significant antitumor activity by inhibiting proliferation of K-562 cells (IC50 = 305.31 nM). By simultaneously targeting IMPDHII and HDAC1, this compound demonstrates a synergistic antitumor effect, suppressing tumor cell proliferation and inducing apoptosis. IMPDHII/HDAC1-IN-1 can be utilized in the study of cancers such as chronic myeloid leukemia (CML).