Fig. 7: Schematic representation of the excited-state processes in the octupolar dye O.

Green hexagon represents the triazine electron acceptor, yellow circles are the electron donors and the orange shading stands for the electronic excitation. Photochemical symmetry breaking is reversible whereas solvent-driven SB is irreversible and leads to the efficient funneling of the excitation into a single arm where it drives chemical reaction (charge separation coupled with the alkyne–allene isomerization). The excess negative charge acquired by the triazine unit as a result of the reaction is delocalized back into the spectator arms (magenta arrows and shading).