The new compound, thiosemicarbazonse, and its metal complexes were synthesized. The compounds were characterized by analytical methods and various spectroscopic (infrared, magnetic, thermal, 1H, 13C NMR, electronic, and ESR) tools. The applications, moreover, include the computational details of theoretical calculations (DFT) for complexes. The compounds were subjected to antimicrobial, antioxidant, antidiabetic, anticancer, and ROS studies, as well as EGFR-targeting molecular docking analysis. Quantum chemical computations were made using density functional theory (DFT), B3LYP functional,...