Used as an analytical reagent in the detection and determination of certain metal ions, particularly in spectrophotometric methods. It acts as a chromogenic agent, forming colored complexes with metals such as copper and iron, which allows for quantitative analysis in environmental and biological samples. Also employed in research settings for studying reaction mechanisms involving nitroaromatic compounds. Its hydroxyl and nitro functional groups contribute to its ability to participate in hydrogen bonding and electron transfer processes, making it useful in the development of sensors and diagnostic tools.