HDAC9 and neoplasm: Hybrid 4 demonstrated nanomolar inhibition of both c-Met (IC50 = 0.71 nM) and HDAC1 (IC50 = 38 nM) as well as effective antiproliferative activities against EBC-1 (IC50 = 0.058 μM) and HCT116 (IC50 = 1.3 μM) tumour cell lines, in each case displaying enhanced potency over reference class-I HDAC inhibitor chidamide and the parent c-Met inhibitor.