The external test set was built to contain co-crystallization data of pharmaceutical co-crystal of anti-inflammatory, antitubercular, nootropic, and anti-depressant drugs from both the scientific literature and in-house experimental cocrystallization screening. 134 co-crystallization data were collected in-house, via co-crystallization lab experiments (Supporting Tables S6, S5, S9, S8, S10, S7). Co-crystal formation was tested via mechanochemical (grinding and liquid-assisted grinding) and solution-based synthetic techniques (slurry and slow evaporation) , with at least three replicates and by changing the polarity of the solvent in syntheses involving its use. The co-crystal formation was investigated comparing the Fourier transform infrared (FT-IR) spectrum of the powder samples obtained with those of the starting materials, and confirmed by solid-state NMR. We report the FT-IR spectrum of the novel co-crystals in the Supporting Information (Supporting Figs. ). The resulting external test set collects 364 molecular pairs of which 129 are co-crystals and 235 non-co-crystals.