γ-Cyclodextrin can be used to control the orientation of alkenes and direct their photodimerization into specific stereoisomers. This document reports on research investigating the use of γ-cyclodextrin to promote the selective photo-heterodimerization of cinnamic acid and coumarin derivatives. It was found that γ-cyclodextrin forms inclusion complexes that favor the head-to-head heterodimer product over homodimers. Substituents on the alkenes influence complex formation, with sterics playing a leading role. Electron-withdrawing groups may also help stabilize hetero-complexes through weak interactions. Future work will further elucidate the interactions governing complex