HDAC-IN-39 (compound 16c) is a potent HDAC inhibitor, with IC 50 values of 1.07 μM ( HDAC1 ), 1.47 μM ( HDAC2 ), and 2.27 μM ( HDAC3 ), respectively. HDAC-IN-39 also significantly inhibits microtubule polymerization. HDAC-IN-39 induces cell cycle arrest at the G2/M phase. HDAC-IN-39 displays promising anticancer activity against resistant cancer cells.