j-IR-vis was most challenged at predicting alcohols, amines, ethers, esters, and ketones (Fig. ). While alcohols and amines possess O-H and N-H stretching vibrations that produce strong signals between 3100-3500 cm -1 , we believe that the model struggled to identify these groups due to the quality of IR spectra obtained from the NIST database. The IR spectra used were primarily based on gas-phase data and the O-H and N-H stretching signals possessed lower intensities than what would be expected for these functional groups. Ether functional groups exhibit only a C-O stretch between 1000-1300 cm -1 ; however, this signal is contained in the fingerprint region (< 1500 cm -1 ). The fingerprint region in IR spectra contains many stretching and bending vibrations common to organic molecules (e.g., C-C, C-O, C-N) and as such it may be difficult for j-IR-vis to distinguish the C-O signal from other signals in this region. Lastly, ketones and esters show strong signals for the C--O stretch between 1700-1750 cm -1 ; however, neither of these functional groups exhibit another vibration that allows them to be definitively identified over other carbonyl-based functional groups as seen for aldehydes, amides, and carboxylic acids.