The invention includes an enantioselective indicator-displacement assay useful to determine enantiomeric excess (ee) enantiomeric samples calorimetrically. Determination may be by inspection of color with the naked eye, spectrographic measurement, or mathematical calculation. Concentration may also be determined. The assay may involve two independent absorption measurements. On suitable group of enantiomeric molecules to be assayed include .alpha.-hydroxyacids. The inherent relationship between the absorbance of the indicator-displacement ensemble and the overall concentration and ee of the analyte is established through solution equilibria. The invention also includes use of the assay in drug screening and manufacturing, high throughput screening of catalysts and kits for use in conducting assays of the invention.