Allessa GmbH

Allessa is a major European custom and toll manufacturer of fine chemicals with more than 100 years of experience in the synthesis of small molecules and polymeric substances.

We offer a broad variety of technologies and complex synthetic capabilities in our flexible multipurpose plants (for example low-temperature, organometallics and high pressure chemistry).
Both companies, Allessa GmbH and Allessa Produktion GmbH operate from three production facilities at the Rhine-Main area, Frankfurt-Fechenheim, Frankfurt-Griesheim and Frankfurt-Höchst. Allessa operates the Frankfurt-Fechenheim site also as a industrial park. Numerous companies utilize the excellent infrastructure and the comprehensive service portfolio.

Core technologies

  • Boronic acids chemistry
  • Friedel-Crafts
  • Grignard chemistry
  • Hydrogenation
  • Low temperature chemistry
  • Suzuki coupling


Allessa is ISO 9001, 14001 and 50001 certified.


1870 Foundation of Frankfurter Anilinfabrik von Gans und Leonhardt in Fechenheim
1879 The Fechenheim site Hosts the world´s largest Azo dye production plant
1925 Foundation of I.G. Farben
1952 Foundation of Cassella Farbwerke Mainkur AG
1996 Acquired by Höchst AG
1997 Foundation of Clariant AG
2001 Foundation of AllessaChemie GmbH
2004 Foundation of AllessaSyntec GmbH
2012 AllessaChemie and AllessaSyntec Team up to form Allessa GmbH
2013 Acquired by ICIG, integrated into WeylChem Group of Companies


Allessa GmbH
Alt-Fechenheim 34,
60386 Frankfurt am Main, Germany

Phone +49 69 4109-01
Fax +49 69 4109-2100


Bernd Mucha (Chairman)
Wolfgang Böhm