In thin films of EPI, it was previously reported that the substrate temperature during film deposition can have a significant impact on the resultant transistor performance.5 The strong influence of preparation conditions on film structure is well known, and it was recently shown for another hydrogen-bonded pigment, Tyrian purple, that a new polymorph can be induced at low substrate temperatures.10 The performance variation in transistors produced from EPI deposited at different substrate temperatures points to structural differences in the thin films which are yet to be characterized.