Physicochemical properties of a new organic dihydrogenmonophosphate [C2H6N5] H2PO4 are discussed on the basis of X-ray crystal structure investigation. This compound crystallizes in the orthorhombic F2dd group with a = 6.082(3) angstrom, b = 13.531(14) angstrom, c = 37.075(8) angstrom, V = 3051.0(1) angstrom(3), and Z = 8. Crystal structure was solved and refined to R = 0.026, using 915 independent reflections. It can be described by inorganic layers parallel to (a, b) planes, situated at z = 0, 1/4, 1/2 and 3/4. Between these layers are located the organic cations through numerous hydrogen bonds producing a three-dimensional network. Each organic entity is connected to two neighbors by pi-pi stacking interactions. A characterization of this compound by solid-state C-13, N-15 and P-31 MAS NMR and IR spectroscopies is also reported.