Cyclohexylammonium 4-nitrobenzoate (CYH4NBA), an organic nonlinear optical material, was grown by slow evaporation and characterized via elemental analysis, single crystal XRD, thermal analysis, and dielectric studies. FTIR and NMR confirmed structure, while UV–Vis-NIR spectroscopy showed a cutoff at 263.24 nm. DFT calculations analyzed HOMO–LUMO gap and electrostatic potential. CYH4NBA exhibits optical limiting properties, moderate melting point (160°C), and high third-order nonlinear susceptibility (2.58 × 10−6 esu), suitable for optical applications.