Data 22-12-05-data: original molecular XANES data created from Ghose et al. 23-04-26-ml-data: machine learning-ready data which is prepared in the format required by Crescendo. 23-05-03-hp: hyper-parameter tuning results from 23-04-26-ml-data. 23-05-05-ensembles: ensemble results from 23-04-26-ml-data. 23-05-11-ml-data-CUTOFF8: a special machine learning-ready dataset constructed by a unique partitioning: only molecules with less than or equal to 8 atoms/molecule are used for training/validation, the rest are used for testing. Funding This research is based upon work supported by the U.S. Department of Energy, Office of Science, Office Basic Energy Sciences, under Award Number FWP PS-030. This research also used theory and computational resources of the Center for Functional Nanomaterials, which is a U.S. Department of Energy Office of Science User Facility, and the Scientific Data and Computing Center, a component of the Computational Science Initiative, at Brookhaven National Laboratory under Contract No. DE-SC0012704.