Superimposing all HSQC peaks in the dataset reveals the typical diagonal correlation where aliphatic peaks are situated at lo wer ppm ranges in the C and H spectra, and aromatic peaks occur at higher ppm shifts (Supplementary Figure ). For certain compounds containing aldehyde and/or carboxylic acid groups, peaks occasionally appeared in the incorrect region of the spectrum due to folding; although they were expected to appear around 180 ppm in the carbon spectrum, they were sometimes mirrored to around 30 ppm. This folding phenomenon arises when the chosen spectral width for the experimental data is insufficient to encompass all the signa ls within the spectrum (Supplementary Figure ). Since these incorrect peak locations of the ground truth molecules would be consistent when comparing all simulation techniques, we decided to retain these molecules in the database. Supplementary Figure showcases an exemplary subset of the molecules contained in the final set.