Crystals of 2(2-ammonium ethyl ammonium) ethanol monohydrogenmonophosphate monohydrate: (C 4 H 14 N 2 O)HPO 4 ·H 2 O abbreviated as AEEHP, were prepared and grown at room temperature. The AEEHP crystallizes in the monoclinic system with the P2 1 /a space group. Its unit cell dimensions are: a=4.8236(2), b=28.429(2), c=7.0711(6) Å, and β=94.881(4)° with V=966.14(11) Å 3 and Z=4. The structure of this compound was determined by using X-ray data collection on single-crystal. The AEEHP structure is built up from infinite inorganic HPO 4 2− chains parallel to the a-axis, alternating with infinite chains of H 2 O molecules. These chains are interconnected by organic groups so as to build a three dimensional arrangement. In the present work, we describe the crystal structure, thermal behavior and IR analysis of this new compound.