JAK/HDAC-IN-2 is a potent 2-amino-4-phenylaminopyrimidine JAK/HDAC dual-target inhibitor. JAK/HDAC-IN-2 potently inhibits HDAC3/6 and JAK1/2 at nanomolar levels. JAK/HDAC-IN-2 has proapoptotic activity and inhibits histone deacetylation and STAT3 phosphorylation. JAK/HDAC-IN-2 presents remarkable antiproliferative activity in both hematological malignancies and solid cancers.