Threshold simulations reveal a similar energy landscape structure as found for the GAZCES co-crystal, with separate funnels containing structures α and β (Fig. ). Because the simulations were run without space group constraints, a pathway could be found between the polymorphs. This connection was located when the lid energy was 40 kJ mol -1 above α, which has the slightly (1.4 kJ mol -1 ) lower calculated lattice energy of the two known polymorphs. The relatively high energy barrier is unsurprising, considering the breaking of hydrogen bonds required to transform between α and β, along with substantial reorientation of the molecules.