A new mixed-ligand zinc (II) coordination compound formulated as [Zn(IAA)2(NA)2]⋅2H2O was synthesized using indole-3-acetic acid (IAA) and nicotinamide (NA) ligands and investigated by combined experimental and computational methods. The composition and coordination environment of the complex were determined by elemental analysis, IR, and UV–Vis spectroscopy. The obtained results revealed that the IAA ligand coordinates through the carboxylate group, whereas nicotinamide binds to the Zn(II) ion via the pyridine nitrogen atom. To investigate the electronic structure and stability of the complex, Density Functional Theory (DFT) calculations were performed using the CAM-B3LYP functional and LANL2DZ basis set within the Gaussian-16 software package. Geometry optimization confirmed the energetically favorable structure of the complex. Frontier molecular orbital analysis, including HOMO– LUMO energy levels and molecular electrostatic potential mapping, demonstrated charge redistribution and donor–acceptor interactions within the coordination sphere. The theoretical results showed good agreement with the experimental data, confirming the stability and electronic features of the synthesized Zn(II) complex.