Photochemistry is at the heart of highly efficient energy conversion in living matter and may be the basis of novel technologies aiming to a sustainable footprint of human activities on the planet. As an example, photoinduced isomerization reactions in specific molecules, such as norbornadiene, can provide medium/long term storage of energy, that can be released, on demand, as thermal energy. In these processes, photon absorption triggers an ultrafast event on the attosecond (as) to few-femtosecond (fs) time scale. Little is known about what happens just after photoexcitation as the sudden electron dynamics and follow-up relaxation are complex phenomena. This shortcoming is due, firstly, to the current ~100 fs limit in time resolution when performing element-sensitive time-resolved spectroscopy, such as X-ray absorption spectroscopy (XAS). Our proposal is to study the norbornadiene/quadricyclane cycloaddition reaction via attosecond-resolved XAS at the carbon K-edge. The possibility to conduct XAS measurements with extreme temporal resolution is enabled by our novel parametric waveform synthesizer (PWS) source. The PWS delivers sub-cycle IR transients and isolated attosecond pulses (IAPs) spanning from the XUV to the water-window region, obtained via high-harmonic generation (HHG), therefore intrinsically synchronized. In order to study organic gas-phase samples, a new sample delivery mechanism and differential pumping system will be developed during this project.