The present invention is directed to methods of producing THC from CBD utilizing non-harsh methodology and resulting in substantially increased yields, as well as devices built upon these novel methods. The methods and devices are material efficient, and in certain embodiments, solvent-free. In particular, in certain embodiments, these methods and related devices are suitable for commercial production of THC from CBD. Furthermore, in certain embodiments, the present invention provides methods of producing THC from CBD in manner that affords tunability to select the ratio of THC-8 to THC-9.