In its early years, the company focused on importing luxury goods from India, China and South America, and Cassel and Reiss also founded a sugar refinery in 1812.

In 1870, Friedrich and Leo Gans founded a dye factory at Mainkur in Fechenheim with their brother-in-law Bernhard Weinberg and the chemist August Leonhardt, called Frankfurter Anilinfarbenfabrik von Gans und Leonhardt.

In 1900, Arthur Weinberg established a pharmaceutical division of the company, and collaborated closely with his friend Paul Ehrlich, the founder of chemotherapy.

After World War II the company was reestablished as Cassella Farbwerke Mainkur AG and the rebuilding under Richard von Szilvinyi and Werner Zerweck's leadership proved very successful, making the company the "darling of the stock exchange" in the 1950s.

In the mid 1950s BASF, Bayer and Hoechst bought the controlling majority with 25.1% each, while the remaining shares were owned by smaller shareholders.

In 1999, Hoechst merged with Rhône-Poulenc to form the French-German company Aventis with headquarters in Strasbourg and the main research and production facilities in Frankfurt.