The (E)-2-(2-hydroxystyryl)quinolin-8-ol (abbreviated as HSQ) molecule was synthesized and characterized. The ESIPT, solvatochromism properties, electronic structure, and ground and excited electric dipole moments of this molecule were measured using absorption and fluorescence spectra recorded in 13 different solvents. Its electronic structure via electronic transitions was investigated to find the quantitative values of solvatochromism properties by LSER calculations. The ESIPT mechanism was clarified; ground and excited dipole moments were determined using solvatochromic shift methods. The DFT (B3LYP)/6-311$++$G(d,p) method and basis set with potential energy surface (PES) calculations of proton transfer were used to explain the ESIPT mechanism. NBO analysis, NLO properties, and behavior under an electric field were also determined.