Research in the Groeneman group focuses on the chemistry of the organic state in terms of both photoreactivity and thermal extension within these molecular solids. The photoreaction that is investigated is based upon the solid-state [2 + 2] cycloaddition reaction. They utilize this light induced reaction with the goal of synthesizing unique molecules that contain cyclobutane rings. Within the area of thermal expansion, Groeneman researches the ability to control the direction and magnitude of the tensors of expansion by varying the type and strength of non-covalent interactions that sustains these solids. In a similar manner, he also investigates the role of motion capable and incapable components play on the overall thermal expansion within these molecular crystals.