5-Methylindole-3-carboxaldehyde was used in the synthesis of novel flexible tripodal ligand derived from 3-methylindole and its mononuclear Zn(II),Cu(II), Ni(II), Hg(II) and Pd(II) complexes. Reactant for preparation of: · Tryptophan dioxygenase inhibitors pyridyl-ethenyl-indoles as potential anticancer immunomodulators · Antimicrobial agents · Anti-proliferative agents · Antiandrogens effective against multiple clinically relevant androgen receptor mutants · Anticancer agents · Inhibitors of Mycobacterium tuberculosis protein tyrosine phosphatase B · Bovine viral diarrhea virus (BVDV) inhibitors · Potent thermal sensitizing agents · Analogues of marine alkaloid nortopsentin as anticancer agents · β3-adrenergic receptor agonists