This study explores two fundamentally different behaviors of benznidazole in its various forms. First, the charge transport behavior describes how electric charges move through the molecule, while the nonlinear optical properties reflect how the material responds to intense electromagnetic fields. These behaviors were analyzed using the non-equilibrium Green’s function (NEGF) formalism combined with density functional theory (DFT). In this study, two s-cis forms (C2 and C4) and one s-trans form were investigated as molecular switches, while C2 and C4 were specifically evaluated for nonlinear optical (NLO) activity. The influence of electrode material (Pt, Au, Ag) and binding sites (bridge, hollow, top) on transport efficiency was assessed, with platinum at the bridge site providing optimal current output and switching performance. Among all configurations, the C4 form showed the highest current output (1556 nA). The current ratio between C4 and Trans was maximal, indicating effective switching. This enhanced conductivity was associated with a narrower HOMO–LUMO energy gap and molecular projected self-consistent Hamiltonian (MPSH) orbitals. Additional descriptors, including transmission pathways, molecule–electrode coupling, transmission spectra, and stabilization energies (E2), further supported these findings. Beyond charge transport, benznidazole also exhibited a strong NLO response. Calculations revealed hyperpolarizability values far exceeding those of the benchmark urea. Complementary descriptors, including dipole moments, global hardness, and softness, reinforced the NLO activity, identifying the C2 form as particularly efficient for optical modulation. These findings suggest that benznidazole-based systems hold strong promise for integration into nanoscale molecular electronics and photonic devices.

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