In this study, the preparation and analysis were carried out for a novel organic–inorganic hybrid crystal 4-aminopyridinium nitrate (4-APN), which was effectively synthesized by the slow evaporation method. The crystal structure at 300(2) K was found by single crystal X-ray diffraction analysis. The 4-APN crystallized in the monoclinic form with the C12/c1 space group. The 4-APN structure is established by N—H \(\ldots\) O and C—H \(\ldots\) O interactions. Raman spectroscopy was used to detect the vibrational modes that correspond to the nitrate and aminopyridine groups. The UV–Vis-NIR spectra revealed a broad transmittance between 300 and 1100 nm. The bandgap was found to be 4.30 eV. Photoluminescence spectroscopy and chromaticity plotting were used to explore the luminescent features of 4-APN. The 4-APN crystal showed different light emissions at 342 nm, 534 nm, and 645 nm, which can be helpful for light-emitting displays. The 4-APN sample was found to have a second harmonic generation efficacy that was 0.95 times the KDP sample. Dielectric tests demonstrate that the dielectric constant and dielectric loss are minimal and temperature-independent at higher frequencies. The Nyquist graph verifies the single-phase nature of the 4-APN sample by displaying a single semicircular arc at various temperatures. Experimental results indicate that 4-APN crystals can be applied in optoelectronic devices.
