As a generous patron, she supported outstanding female scientists through her foundation. She established her foundation out of solidarity with her home city of Bonn. Accordingly, the Gielen-Leyendecker Foundation specifically promotes science and research in Bonn – this includes the Beethoven-Haus, the Kunsthistorisches Institut and the Franz Joseph Dölger Institute at the University of Bonn.
Anne-Liese Gielen was very close to the Max Planck Society through former President Hubert Markl and as a Private Supporting Member. She provided generous support for the extension of the Bibliotheca Hertziana Max Planck Institute in Rome, and for the career advancement of two female Max Planck scientists – Letizia Paoli, now a professor at the Leuven Institute of Criminology (LINC), and Ilme Schlichting, currently a director of the Max Planck Institute for Medical Research.
In 2013, the Foundation established a Gielen-Leyendecker Research Group in cooperation with the Max Planck Society, through which Dr. Susann Fiedler, an outstanding scientist, is being given crucial support in the development of her career.