Inhibition of histone deacetylase (HDAC) enzymes is emerging as an innovative and effective approach for the treatment of cancer. Hundreds of hydroxamic acid derivatives were designed and tested in silico for their interaction with histone deacetylase (HDAC) enzyme. A series of semi/thiocarbazone hydroxamic acid derivatives with moderate to good G-score were designed, synthesized and evaluated for their ability to inhibit cell proliferation in cancer cell lines. Many compounds showed encouraging anti-proliferative activity against the cancer cell lines, MCF-7, HCT-15 & Jurkat. Compounds C4 & C10 showed promising activity against all the three cell lines, while compound C6 and C12 showed colon cancer cell specific inhibition.