A Schiff base ligand is synthesized from the condensation of dapsone and 4-dimethylaminobenzaldehyde using cashew nut shell liquid (CNSL) anacardic acid as a green and natural effective catalyst via solvent-free simple physical grinding technique. Furthermore, metal(II) complexes Co(II), Cu(II) and Zn(II) coordinated by a new Schiff base ligand (L) were prepared. The composition of Schiff base ligand and its metal(II) complexes were analyzed by various analytical techniques. The Schiff base ligand and its complexes have been tested in vitro to evaluate their antimicrobial activity against Escherichia coli, Staphylococcus aureus and Candida albicans using well-diffusion method. It has been found that the Schiff base ligand and its complexes show significant antimicrobial activity against all tested bacterial species. Molecular docking study of Cu(II) complex with target protein HER2 has revealed good binding energy.