Two novel compounds, [Zn(SCN)4] (C5H7N2)2 (I) and (C5H7N2)NCS (II), were successfully synthesized and grown at room temperature by slow evaporation. The investigation of compound's properties was occurred using various techniques such as IR, thermal analysis, and single X-ray analysis. X-ray diffraction shows that both compounds (I) and (II) crystallizes in the monoclinic system with the space group P 21/c." Compound (I) contains a distorted tetrahedral [Zn(SCN)4] anions. According to crystal packing analysis, the [Zn(NCS)4]2− anions and 2-aminopyridine cations are linked via N–H...S hydrogen bonds. Compound (II) consolidates the stacking of the crystal by forming an intriguing three-dimensional network via N–H...N, C–H...S, C–H...π, and π...π intermolecular interactions between 2-aminopyridinium and NCS. The vibrational modes of the various functional groups contained in both compounds were investigated using FT-IR. Hirshfeld surface analysis was performed to investigate the short contacts and hydrogen bonds in the compounds. To get further insights into the molecular properties, NLO, NBO, electrostatic potential, molecular orbital, and QTAIM analyses were performed. Explorations of impedance spectroscopy on (I) and (II) reveal fascinating electrical behavior. It is a useful material for the development of photonic and non-linear optical devices due to the increased dielectric constant and dielectric loss with frequency variation. In the [273–623 K] ranking, the thermal behavior shows a phase transition and the decomposition of both complexes. Finally, the compound's antioxidant activity was tested to reveal a high chelating power which is confirmed by ESP values around sulfur atoms and the QTAIM and NCI-RDG calculation.