The workshop on "The Interplay of Molecules and Membranes" took place at the campus of the Université Libre de Bruxelles on 28 - 30 April 2025. The workshop brought together speakers from the fields of Chemistry, Physics, and Biology around the question how molecules and ions interact with and cross lipid membranes, addressing different aspects of natural and synthetic transport systems for active transport, the interaction between synthetic molecules and membranes, and much more. Joachim was an invited lecturer and presented the work of the two groups on “Light-driven halide pumping in protein crystals, detergent micelles, liposomes, and living cells”.