Lantanilic acid is primarily used in analytical chemistry for the detection and separation of certain metal ions due to its chelating properties. It forms stable complexes with rare earth metals, making it valuable in the purification and extraction processes of lanthanides from mixed ores. This selectivity is exploited in solvent extraction techniques to isolate specific lanthanide elements, which are critical in manufacturing phosphors, catalysts, and high-strength magnets. Additionally, lantanilic acid has been investigated as a reagent in spectrophotometric methods for quantitative analysis of metal ions in environmental and industrial samples. Its ability to form colored complexes allows for sensitive detection at low concentrations.