1-methyl-4-[2-(3-methoxy-4-hydroxyphenyl)ethenyl)]pyridinium] hydrogensquarate monohydrate (1) has been synthesized and its structure obtained by single crystal X-ray diffraction. Optical properties have been elucidated by means of linear-polarized solid state IR-spectroscopy, UV-spectroscopy as well as nuclear magnetic resonance and thermal analysis. The polarization tool of oriented colloid suspensions in nematic host is used. Quantum chemical calculations have performed with a view to obtaining the electronic structure and optical properties of the novel compound. The compound crystallizes in the space group P-1 and the structure consists of infinite layers, resulting from intermolecular OH…O=C(Sq) (2.684 Å) and (Sq)OH…OH2 (2.575 and 2.850 Å) hydrogen bonds between the cation and anions as well as solvent molecules.