Equations of state (EoSs) show how the thermodynamic variables of temperature, pressure and volume are inter-related. The ideal gas law, PV = nRT, is an example of an EoS which is used as a simple but effective model to explain the properties of gases. EoSs can also be applied to solids, where they can be used to show how energy changes when the solid experiences changes in its environment. Previous work has shown that these data are a sensitive check of the accuracy of computational simulations. In this beamtime we will derive the EoSs of two H-bonded solids, the amino acid alanine and the analgesic paracetamol, which both show unusual trends in their unit cell dimensions on compression which imply that subtle structural modifications occur which alter the way the solid accommodates the increasing pressure.