Abstract The effect of substituents on the geometry of thiobenzophenones is derived from the arylthiocarbonyl UV-absorption at 300-375 nm. Hammett σ-constants can be correlated with the energy of the n [RIGHTWARDS ARROW] π* transition of the thiocarbonyl group near 600 nm. Absorption at 230 nm can be ascribed partly to aryl-aryl interaction by comparison with substituted diarylethylenes.
