Laboratoire de Chimie de Coordination (LCC), CNRS, Toulouse, France;Prof. Azzedine Bousseksou is an Exceptional Class Research Director at the CNRS and founder and leader of the Switchable Molecular Materials team at the Laboratoire de Chimie de Coordination in Toulouse, where he previously served as Director. He was also the coordinator of the European COST Network on Spin Crossover phenomenon and member of the CNRS National Committee for the research evaluation (2000-2004 and 2011-2015).A member of the French Academy of Sciences, he has made major contributions to spin-crossover molecular materials from fundamental cooperative switching to nanoscale and device-oriented systems. His research links molecular design and collective behaviour with mechanical, optical and electronic responses, multifunctionality and nanostructuration. He is member of the European Academy of Sciences, member of the European Academy of Sciences and Arts and Founding member of the Algerian Academy of Science and Technology. He was awarded the Prize of the French Society of Chemistry, the Langevin Prize of the French Academy of Sciences, the prestigious Silver Medal of the CNRS, the DGRSDT Algerian research distinction, the Chemistry research Prize, the Korean Magnetism society Prize, the Montpellier University Medal and the ‘‘Grand Prix’’ Süe of the French Society of Chemistry.

School of Chemistry, University College Dublin, Dublin, Ireland;

School of Chemistry and Chemical Engineering, Queen’s University Belfast, Belfast, United Kingdom;Prof. Steven E. J. Bell is Professor in the School of Chemistry and Chemical Engineering at Queen’s University Belfast. He is Fellow of the Royal Society of Chemistry and a Fellow and President of the Institute of Chemistry of Ireland. He is an elected member of the Royal Irish Academy, where he sits on the council as Vice-president for Research. His research centres on Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS), quantitative vibrational analysis and nano-/microstructured materials. His group has developed Raman methods for probing molecular structure and composition and for challenging real-world analyses. For spin-crossover materials, this expertise provides direct, non-destructive access to changes in metal–ligand bonding, molecular symmetry and structural reorganization across spin-state transitions, complementing magnetic and crystallographic measurements and helping resolve heterogeneous or dynamically evolving states.