QSAR equation with 13C NMR chemicalshifts as independent parameters. The key step of the synthesis is the formation of substituted 2‐phenoxybenzoic acids by Ullmann reaction followed by intramolecular Friedel‐Crafts acylation, leading to methyl‐, carboxy‐, nitro‐, cyano‐, and aminoxanthones as a test set for QSAR investigations. Spectroscopic data (1H and 13C chemicalshifts, IR, UV) of these xanthones