One of the most important characteristics of polymethine dyes is their strong absorption in the ultraviolet, visible and near infrared regions. These properties also enable their use in many areas other than colouring. In this study, the preparation of chloro heptamethine cyanine as a type of polymethine dye was prepared. The preparation was carried out in the solution of quaternary ammonium salt and bisaldehyde in a controlled manner through heating under reflux. The product was characterized by determinations of its molecular weight, melting point, fluorescence, excitation and absorption properties. After wards, the suitability of the product on dye laser was investigated. Dye laser system was performed and, as expected, it was shown that the dye could produce laser light in the intervals where it shows its fluorescence property.