N-((6-methylpyridin-2-yl)carbamothioyl)thiophene-2-carboxamide, C12H11N3OS2 (HL) and its Co(II), Ni(II) and Cu(II) complexes (ML2 type) have been synthesized and characterized by elemental analysis, FT-IR , 1 H-NMR and HR-MS methods. Moreover, HL was characterized by single crystal X-ray diffraction method. The HL crystallizes in the monoclinic crystal system with P 1 21/c 1 space group, Z=4, a=7.2326(8) Å, b=18.3492(16) Å, c=9.7724(9) Å. The [ML2] complex structures were optimized by using B97D/TZVP level. Molecular orbitals of HL ligand were calculated at the same level. Antioxidant activities of the complexes were determined via DPPH and ABTS assays. Anticancer activity of the complex was studied via MTT assay in MCF-7 breast cancer cells.