The landscape of β-cinnamic acid is explored by an extension of the previously reported fluorosubstitution protocol. Solid solutions of mono- and difluorocinnamic acids allow for the generation of a large number of experimental data points, which in conjunction with computational crystal structure prediction results can be used to profile the structural landscape of β-cinnamic acid. The variation in structure types may be caused by geometrical factors, namely shape-size equivalences, and chemical factors through the intermediacy of weak C–H⋯F hydrogen bonds in the solid solutions.