1,3-Diethyl-2-thiobarbituric acid is primarily used in analytical chemistry as a reagent for the detection and quantification of various compounds. It is particularly effective in colorimetric assays, where it reacts with specific substances to produce a measurable color change. This property makes it valuable in biochemical research for analyzing oxidative stress markers, such as malondialdehyde, in biological samples. Additionally, it finds application in the synthesis of heterocyclic compounds, serving as a building block in organic chemistry for creating complex molecules with potential pharmaceutical or industrial uses. Its role in these processes highlights its importance in both research and practical applications.