A new [Co(SCN)4]·2(C5H14N2)·2(CNS), synthesized from a thiocyanic cobalt precursor and homopiperazinium organic cation in EtOH under hot and basic conditions. X-ray diffraction DATA showed that the compound is composed of one Co cation, located on a center of inversion and four thiocyanates anion, and two homopiperazinium co-ligands add to two thiocyanate ions crystallographically independent in a monoclinic unit cell with P21/c space group. N-H∙∙∙S and N-H∙∙∙N interactions form a distinctive ring–like pattern that links units in crystal packing. This work demonstrates an easy fabrication of a new compound with excellent dielectric properties. Additionally, Fourier Transform Infrared (FT-IR) spectroscopy studies the different functional groups. The dielectric study shows that the developed material has a huge dielectric constant εr≈1010. The resulting material also exhibits a reasonably low loss (tang δ < 1) at low frequencies. Hirshfeld surface (HS) was carried out to study the elemental contact of molecules in crystal packing. Theoretical investigations were performed by using DFT-B3LYP functional. The frontier molecular orbital (FMO) and natural bonding orbitals (NBO) analysis are evident for excellent reactivity and charge transfer within the complex. The global reactivity descriptors were calculated to get deep insight into the reactivity and electronic properties of the complex. For the optical and nonlinear optical (NLO) properties, the static polarizability (αo) and hyperpolarizability (βo) were calculated at the same method. The observed remarkable βo value of 58737.93 au is indicating its excellent NLO properties.