Raw data of research article "Dithienylethene-based photoswitchable phosphines for palladium-catalyzed Stille coupling reaction". This research paper describes two photoisomerizable phosphine ligands synthesized based on dithienylethenes whose electronic communication with strong electron-withdrawing groups is switched on and off upon light irradiation. As a result, the σ-donating ability of these phosphines can be efficiently light-controlled. This behavior was transferred to palladium(II) catalytic complexes and exploited to photomodulate the reaction rate of a model Stille reaction.