The combination of time-resolved spectroscopy and nonadiabatic quantum molecular All these properties and the combination with dynamics simulations make them powerful tools for the investigation of electrocyclic photochemistry to gain new insight into this class of reactions. This is demonstrated in the reviewed work on 1,3-cyclohexadiene and its derivatives αphellandrene and α-terpinene. They reveal a real-time picture of the stereo-specificity of electrocyclic reactions and deep insights into its origins. Moreover, in their combination, they reveal evidence for electrocyclic ring-closure pathways that have not been previously observed.