 light is recognized as an accurate and non-invasive tool for stimulating excitable cells. Here, we report on a non-genetic approach based on organic molecular phototransducers that allows wiring and electrode-free tissue modulation. As a proof of concept, we show photo-stimulation of an in vitro-cardiac microphysiological model mediated by an apophilic azobenzene compound that preferentially dwells in the cell membrane. Exploiting this optical-based stimulation technology could be a disruptive approach for highly-resolved cardiac tissue stimulation. This article was authored by V. Vero, K. Shani, H. A. M. Ardona, and others.