Although laboratory errors in reported data are always possible, recent publications provide good examples to shed light on another existing reason for discrepancies in data. A wide range of solubility has been reported for compounds from the same family, despite identical pH conditions and supporting electrolytes. Our computed pK a values (see SI Sect. V) suggest that in each study, these molecules have very similar acidic or basic characteristics and exist in ionic form in the solutions studied, which would typically result in high solubility. This discrepancy can be attributed to crystallization processes. The low-soluble compounds will likely form more stable crystals even if they are chemically similar. In other words, the molecular packing in the crystal is very sensitive to the molecular structure and this can lead to large changes in crystal binding energy (polymorphism impact).