Excited state dynamics of 3,6-diaryl-1,2,4,5-tetrazines. Experimental and theoretical studies

► The lowest excited states of 3,6-disubstituted 1,2,4,5-tetrazines are of nπ* nature, regardless of the substituents. ► The absorption spectra can be adequately interpreted using TD-DFT calculations. ► The weak fluorescence is associated with the presence of a low-energy ππ* excited state. ► UV excitation produces a high-energy ππ* excited state which decays relatively slowly and shows upper-excited state emission.