In Memoriam: Prof. Dr. Harald Hillebrecht (1960–2024)

It is with profound sorrow that we commemorate the life and scientific legacy of Prof. Dr. Harald Hillebrecht, who passed away far too early on 26 October 2024 at the age of only 64. A distinguished scholar, inspiring mentor, and deeply respected colleague, Harald Hillebrecht's contributions to solid-state and inorganic chemistry have left an enduring mark on our field. Harald Hillebrecht was born on 10 July 1960 in Weingarten, Baden- Württemberg, Germany. He pursued his studies in chemistry at the Albert-Ludwigs-Universität Freiburg from 1981 onwards, becoming a scholar of the Studienstiftung des deutschen Volkes in 1984. Having completed his diploma and doctoral work on halogenides and halogenometallates of transition metals under Gerhard Thiele's supervision, he expanded the scope of his research interests as a postdoctoral researcher associated to Hans Georg von Schnering at the Max Planck Institute for Solid State Research in Stuttgart. He completed his habilitation in Inorganic Chemistry at Freiburg University in 1997 and became a professor at the University of Bonn in the same year. After a move to the University of Bayreuth in 1999, he returned to Freiburg in 2002 to take over the chair for Inorganic Solid-State Chemistry. Throughout his academic career, he demonstrated exceptional dedication to teaching, playing a crucial role in establishing and nurturing the binational Regio Chimica Bachelor programme in cooperation with the Université de Haute Alsace in Mulhouse, France. In addition, he was a member of the scientific advisory board of the Max Planck Institute for Chemical Physics of Solids. Harald Hillebrecht's research spanned a wide range of topics within solid-state chemistry focusing on structure-property relationships of mainly hard materials, but also intermetallic phases, perovskite phases for solar cells, thermoelectric materials, and during the last years non-linear optical materials. Chemically seen, borides and carbides were his most beloved materials, obtained by high-temperature syntheses. His work demonstrated a remarkable combination of scientific curiosity in new materials, crystallographic and structural insights, and openness to new ideas and concepts. Beyond his research achievements, Harald Hillebrecht was an empathic mentor. His students and collaborators remember him for his sharp intellect and tongue, his readiness to challenge assumptions – ”Nix glauben!” –, and his ability to foster creative, independent thinking. As one colleague noted, he occasionally stepped back to support and help others grow. Harald Hillebrecht's passing leaves a significant void. We remember him not only as a brilliant scientist but also as a generous colleague and mentor whose enthusiasm for chemistry and commitment to community enriched the lives of so many. We extend our condolences to his family, friends, and all who had the privilege to work with him. His memory will be cherished with deep respect.