(Z)-Thiazole Orange iodide is an asymmetric cyanine dye with fluorescence highly dependent on its local environment. In solution, it is generally non-fluorescent; however, its fluorescence increases by a factor of one thousand when bound to double-stranded DNA and RNA (dsDNA or dsRNA). The compound's absorption maxima while complexed with DNA is 509 nm, and its emission maxima is 532 nm. (Z)-Thiazole Orange iodide solutions are widely utilized for determining the percentage of reticulocytes in human peripheral blood using microscopy and flow cytometry.