Imidazolium <i>versus</i> phenylalaninium hybrid salts: supramolecular control of electronic, nonlinear optical and bioactive properties

space group but exhibit distinct packing motifs: a compact chloride-stabilized network in (1) and a more open, highly polarized iodide-based framework in (2). DFT calculations show that compound (2) possesses a significantly reduced HOMO-LUMO band gap, higher molecular softness, and enhanced intramolecular charge transfer, leading to a first hyperpolarizability nearly three times larger than that of (1). FT-IR and RDG analyses confirm stronger charge-assisted N-H⋯I interactions in (2), consistent with its superior electronic polarization. Biological assays further demonstrate that compound (2) exhibits markedly enhanced antioxidant and antibacterial activities, attributed to its imidazolium-based charge distribution and iodide polarizability. Together, these findings establish clear structure-property relationships and highlight the effectiveness of combining heterocyclic amino acids with highly polarizable halides to design multifunctional organic-inorganic materials with promising NLO and bioactive potential.