The principles for constructing diarylpolyfluoromethine dyes with the
[4-(CH3)2NC6H4(CF=CF)nCFC6H4N-(CH3)2-4']+ X- structure from their difl
uorovinylene predecessors have been developed and their electronic and
F-19 NMR spectra studied. The difluorovinylene shift is these dyes ha
s been shown to be greater than that in their hydrogen analogues.