In this joint collaboration between the Max-Born-Institute, Berlin (Dr. O. Kornilov) and the IPCMS Strasbourg (Dr. J. Léonard & Prof. S. Haacke), we bring together our expertise to investigate the CInt of rhodopsin-mimicking photo-switches using novel tools of femtosecond and attosecond XUV photoelectron spectroscopy (XUPS).