fluorescence probes trans, trans-1,4-bis[2-(2＇,5＇-dimethoxy)phenylethenyl)-2,3,5,6-tetrafluorobenzene (1) and trans, trans-1,4-bis[2-(3＇,4＇,5＇-trimethoxy)phenylethenyl)-2,3,5,6-tetrafluorobenzene (2) show solvatochromic behavior yielding slopes in the Lippert-Mataga equation of -13300 and -13700 cm(-1), respectively. 1 sensitively probes progress in both photoinduced radical and cationic cross-linking. Both 1 and 2 show minor tendencies for trans-cis photoisomerization. Substituted stilbenes such as trans-2-(2＇,5＇-dimethoxyphenyl)ethenyl-2,3,4,5,6,-pentafluorobenzene (1r) and trans-2-(3＇,4＇,5＇-trimethoxyphenyl)ethenyl-2,3,4,5,6-pentafluorobenze (2r) are less solvatochromic in fluorescence but evidence enhanced tendency toward photoisomerization.