The new Schiff base (L) “4‐[(2,4‐dimethoxy‐benzylidene)‐amino]‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydro‐pyrazol‐3‐one” was synthesized from 2,4‐dimethoxy‐benzaldehyde and 4‐amino‐1,5‐dimethyl‐2‐phenyl‐1,2‐dihydropyrazol‐3‐one, and the geometry of Schiff base was characterized and determined by proton nuclear magnetic resonance (1H‐NMR), mass, Fourier transform infrared (FT‐IR), and ultraviolet‐visible (UV‐vis) spectroscopy. Schiff complexes of Ni(II), Pd(II), Pt(IV), Zn(II), Cd(II), and Mg(II) have been prepared by reaction of ion metals with as‐prepared Schiff base. The results showed that synthesized complexes offered 1:2 metal‐ligand ratios. Furthermore, the Schiff complexes were a tetrahedral in complexes Ni(II), Zn(II), Cd(II), and Hg(II), octahedral Pt(II), and square planer complex Pd(II). Additionally, density functional theory (DFT) was applied for calculations of both spectroscopic properties and electronic structure of prepared Schiff bases. Moreover, the Schiff base and its metal complexes have been verified in vitro against Streptococcus, Esherichia coli, Candida albicans, and Candida tropicalis in order to assess their antibacterial potential. The findings indicate that the biological activity augments on complexation reaction.