New heterocyclic azo-schiff base dye (L2) have been synthesized from a reaction of 4-(dimethylamino)benzaldehyde with (E)-5-((1H-benzo[d]imidazol-2-yl) diazenyl) -2amine-4,6-dimethylpyridin (L1) . A new class of Ni(II), Pd(II), and Pt(IV) complexes of azo-schiff base of the type [Ni(L2)2Cl2], [Pd(L2) Cl2] , and [Pt-2amine-4,6-dimethylpyridin. Both ligand and its metal complexes were characterized by the spectroscopic and analytical methods such as mass spectral, 1 H-NMR, FT-IR, UV-Visb.,X-ray, TGA and SEM, elemental analysis, molar conductance measurements and magnetic susceptibility., spectral studies suggest the mole ratio [M:L] was [1:2] for Ni(II) and Pt(IV) metal ions, but [1:1] for Pd(II) metal ion. The structures of theses complexes were elucidated on the basis of different techniques suggest the structures of the prepared metal complexes octahedral geometry for the Ni(II) and Pt(IV) complexes and square planar geometry for the Pd(II) complex. The antibacterial activity of the ligand and prepared metal complexes was also studied against gram positive Staphylococcus aureus and gram negative bacteria Escherichia coli, the antifungal activity of the azo-schiff base and metal complexes against the fungi Alternaria. It is found that some of the complexes are quite effective against fungi Alternaria. In this study the cytotoxicity of Pd(II)-complex on human (PC3) cancer and normal cells were studied using MTT assay. Pd(II)-complex showed selective cytotoxicity against cancer cell line with IC50 = 450 μg/ml, while it was very safe on normal cells line with IC50 = 14554885 μg /ml, respectively for human cells .The results indicate undoubtedly the possibility of using them as antitumor drugs in the field of medicine and Pharmacy against prostate cancer.