This work is a review of the phenomenon of solvatochromism, describing in particular its origin in electronic spectroscopy. The physical basis for the Kamlet-Taft π* scale of solvent strength is reviewed and the contributions of solvent dipolarity and polarizability to this empirical scale are emphasized. We then describe the application of various solvatochromic scales of solvent dipolarity. hydrogen bond donor (acidity) and hydrogen bond acceptor (basicity) strength to retention in chromatography. The use of these and related solute scales in rationalizing retention in reversed-phase liquid and gas-liquid chromatography is presented.