 In this study, researchers have developed a new descriptor called S to measure the strength of noncovalent interactions between two molecules. The descriptor was found to be correlated with the reorganization energy of the photoexcited states or electron pumped charged states in organic polymeric semiconductors. This descriptor can be used to predict the strength of noncovalent interactions between two molecules, which is useful for molecular design and property prediction. This article was authored by Maihui Liu, Xiao Han, Hao Chen, and others.