The isolation, structure determination, and total synthesis of Fluoro Nissl Green, a novel RNA-binding fluorochrome, are reported. Initially obtained in only one part per lo5, via a microwaveinduced synthesis from m-phenylenediamine, the structure was determined by spectroscopic methods to be 3, 8-diamino-lOH-quindoline. The proposed structure was confirmed by a rational synthesis starting from m-phenylenediamine and 2, 4- ...