The development of the new attosecond beamline (P1) will allow us to gain insight on the first principles ruling the electron transfer/charge transfer (ET/CT) processes in optoelectronic materials since the early stages upon excitation. In particular, attosecond X-ray spectroscopy at atom-specific absorption edges offers chemical selectivity and represents one of the most promising research directions in attosecond science. We expect that the combined use of different techniques, besides an inherent risk mitigation procedure, will be a very powerful approach for a comprehensive investigation of ultrafast electronic processes initiated by light absorption. This unparalleled iterative procedure will be only possible thanks to the synergy between the three groups of F. Martín, M. Nisoli and N. Martín.