Based on solvatochromic and thermochromic data for diphenylpolyenes of the general formula H5C6-(CH=CH)(n)-C6H5, with n = 1-4, it has been found that their thermochromism is influenced not only by the polarizability of the medium but also by a conformational effect that is at least as strong as that of their solvatochromism. As shown here, the conformational effect enhances the bathochromic band shift caused by lowering the temperature of the solvent. However, such an effect does not occur in structurally rigid diphenylpolyenes. Consequently, Saltiel's isopolarizability approach does not hold in polyenes. (C) 2015 Elsevier B.V. All rights reserved.