By examining reaction kinetics through the phase transitions of thermotropic and lyotropic liquid crystalline media, several cases of marked reactivity control have been discovered. In lyotropic surfactant media, a number of reactions show marked discontinuities in reaction rates through the transitions from rod-like to disc-like phases. In thermotropic media, we have taken advantage of the phenomenon of reentrance to afford a phase sequence with decreasing temperature in which one proceeds from less ordered (nematic) to ordered (smectic) to less ordered again (reentrant nematic). The thermal isomerization of an indigo dye in such a medium indeed shows anti-arrhenius behavior as a consequence of this phase sequence. We have also found that the atropisomerization of 1,1’-binaphthyl increases in rate through the nematic-smectic and smectic-solid transitions, presumably as a consequence of decreasing the barrier from transition state to product in the more ordered phases. Finally, we have demonstrated that achiral solutes which normally show degeneracy of their enantiomeric twist states can behave as though they have a unique twist sense in a chiral liquid crystal environment. Such effects occur for both polymeric solutes and for substituted oligophenyls. The overall message is : liquid crystals can be utilized as media to achieve control of both reactivity and conformation for a wide variety of organic reactions.