In this study, we report that image data, particularly IR spectral data, can be directly used in unsupervised ML to classify chemical structures. To validate this, we used IR spectral image data from the National Institute of Advanced Industrial and Science Technology (AIST) spectrum database (SDBS) 4 , which comprises wellformatted IR spectral image data. The spectral parts of the images were extracted and converted into data using a pixel-scale dimension vector and hierarchically clustered.