Unlike the other two chromophores, the 7MC spectral lineshape differences from full TD-DFT and TDA are minimal for both absorption and emission, as shown in Figure . Compared to CAM-B3LYP, both M06-2X, and LC-ωHPBE predict broader lineshapes for absorption and slightly broader FTFC spectra for emission, as shown in Figure . This comparison suggests that CAM-B3LYP may underestimate the vibronic progression for absorption, leading to a more narrow absorption lineshape. As the wide distribution of VDEs suggests a potentially flat and anharmonic excited state S 1 surface, we also compared our vibronic lineshape computed with the adiabatic Hessian approach, the lineshape generated with the vertical gradient and adiabatic shift approaches, finding that for planar configurations there is good agreement between methods, whereas for more bent chromophore configurations the adiabatic Hessian produces a broader lineshape, see SM, Figure . This broader lineshape supports that the excited state potential is indeed anharmonic at this geometry for this flexible degree of freedom, leading to a breakdown of the harmonic approximation and contributions from overly broad lineshape within the adiabatic Hessian approach.