The solvent descriptors were reduced to two and three principal components retaining 78.6 and 93.5% information, respectively (Figure , ESI). Moreover, contribution of each of the original five descriptors to new components are given in Figure in the ESI. For example, the first component is highly dominated by electrostatic polarity, asymmetry of sigma profile, and hydrogen bond acceptor strength. The second and the third components are mainly defined by hydrogen bond donor strength and surface area, respectively, showing that all five components are included in the three-component space.