A multi-target inhibitor that potently blocks EGFR and HER2 (IC50s = 2.4 and 16.4 nM, respectively) and inhibits the activity of class I and class II HDACs at nanomolar concentrations (e.g., IC50s = 4.5, 12.6, 13.2, and 11.4 nM for HDAC1, 2, 4, and 5, respectively).