The present work reports, the chemical synthesis, crystallographic description, vibrational study and the nonlinear optical response as well as DFT calculations of a new hybrid compound; namely bis(2,6-diaminopyridinium) sulfate monohydrate, [C5H8N3]2SO4.H2O denoted ([2,6-HDAP] 2SO4.H2O). In fact, concerning the structural part, it deals with the experimental work which includes the chemical preparation and the structural arrangement. In the vibration part, we report the combined experimental and theoretical vibration and the convergence between them. Finally, regarding the nonlinear optical response, we have calculated the magnitude of the first hyperpolarizability and compared to with another compounds.