Detour Ring Index as a Molecular Descriptor for Predicting Gas Chromatographic Retention of Sulfur Polycyclic Aromatics

Prediction of positional isomers in polycyclic aromatic sulfur compounds remains a challenge in analytical chemistry. Here, simple ring‐based topological descriptors derived from Distance/Detour Ring Indices (D/DIr05, D/DIr06, and D/DIr09) are evaluated for benzothiophene and dibenzothiophene positional isomers. D/DIr06 and D/DIr09 show excellent linear correlations with experimental gas chromatographic retention indices ( R 2 = 0.992 and 0.991, respectively), while D/DIr05 exhibits a weak correlation ( R 2 = 0.325), suggesting its utility for classification rather than prediction. The strong performance of D/DIr06 and D/DIr09 reflects their sensitivity to structural variations in ring fusion and substitution patterns. These descriptors offer a simple, efficient, and cost‐effective means for predicting retention behavior and identifying positional isomers, providing valuable tools for quantitative structure–retention relationship studies of sulfur‐containing aromatic compounds.