After the discovery of Fuchsine, the first tri-arylmethane dye of the Rosaniline series, in 1856, it turned out that Fuchsine could not only be used as a dye but was also a key intermediate for other synthetic dyes of this dye class. In the beginning of the 1860s, the number of tri-arylmethane dyes was increasing, especially violets and blues, for example Regina purple, Aniline blue, and a series of sulfonated, water-soluble blue dyes. Notably, by using Fuchsine and Methyl violet as starting materials, the green dyes Aldehyde green, Perkin’s green, Iodine green and Methyl green were obtained. At the end of the 1870s, the basic green dyes of the so-called Malachite series, such as Malachite green, Brilliant green and Victoria green 3B were discovered. The basic dyes of the Malachite series can be treated with fuming sulfuric acid, resulting in the water-soluble green acid dyes Helvetia green, Light green and Guinea green, and the Patent blues. In 1883, a new episode of the tri-arylmethanes commenced by employing the toxic gas phosgene in dye synthesis, resulting in Crystal violet. To overcome the technical and scientific difficulties associated with phosgene, the company Bindschedler & Busch joined forces with BASF. The co-operation was so successful that a series of violet and blue tri-arylmethanes, including Ethyl violet, Victoria blue B, Victoria blue 4R and Night blue were invented. These were followed by several sulfonated acid violets and alkali violets, such as Acid violet 7B, and Alkali violet. The collaboration between these companies also opened the way to a new class of dyes, the di-arylmethanes, of which yellow Auramine was the most successful. One can say a colour boom of synthetic dyes.