Past studies on the thermal mechanisms of azoarene photoswitches have determined three possible mechanisms for the Z → E isomerization reaction. These include rotation about the CNNC dihedral, inversion of the π NN bond, and a hula-twist mechanism where there is a twisting motion about the π-bond, and the aryl groups maintain their relative orientations. Past experimental and computational work on azoarenes shows a preference for the inversion mechanism. Because the 3-substituted photoswitches have significant increases in the t 1/2 , we chose to study these further. Figure shows the photoswitching reaction, λ max , and t 1/2 for the parent 3-hemi-azothiophene. These computations provide the first insight into the photoswitching properties of 3-hemi-azothiophene. Thermal Z → E isomerization can also occur (computed t 1/2 of 56 days). The λ max of both isomers was calculated using wb97-XD/augcc-pVTZ and IEFPCM water , and the t 1/2 was computed using PBE0-D3BJ/6-31+G(d,p) and IEFPCM water .