Formazans are known as nitrogen-rich compounds with the basic structure –NH–N C–N N–. They were first described in the 1890s and have since been extensively studied in the 1940s. Due to their vivid colouration, these compounds have gained considerable popularity. They are of interest and frequently used as dyes and redox-based stains in cell biology. One of the most attractive features of formazan chemistry is its ease of synthesis, which allows the modulation of its properties through structural variation.
