The optimized structures and excited state absorption spectra for all electronic excited states are reported in Figure and S5, respectively. In the S2(ππ*) and the S1(nπ*) minima, the purine chromophore remains planar. However, in the case of the S2(ππ*) minimum the sulfur atom is out of the molecular plane of the purine chromophore, while the sulfur remains in the molecular plane of the purine chromophore in the S1(nπ*) minimum. Similarly, the purine chromophore remains planar in the case of the T1(ππ*) and T2(nπ*) optimized geometries, but the sulfur atom is out of the plane of the purine chromophore in the T2(nπ*) minimum, while the sulfur atom remains in the plane of the chromophore in the T1(ππ*) minimum at the TD-PBE0/IEFPCM/6-311+G(d,p) level of theory.