A new series of push-pull arylvinyldiazines has been efficiently prepared by aldol condensation between the appropriate methyldiazine and aromatic aldehyde. The optical absorption and emission properties of these chromophores were studied in different solvents and media. These compounds act as polarity sensors with a strong positive emission solvatochromism. This behavior suggests a highly polar emitting state, which is characteristic of compounds that undergo an internal charge transfer upon excitation. These molecules also exhibit halochromic properties and are potential colorimetric and luminescence pH sensors. The second-order nonlinear properties have been investigated for some of the compounds, and large and positive μβ are obtained, in particular, for pyrimidine derivatives.

Electrochemical or chemical dimerization of electron-rich ferrocenylmethylenepyran 1 gave the first dimetallocenylbispyrylium salt 2 known today, through a reverse process that implies reductive C−C bond breaking. Deprotonation of the bispyrylium salt 2 afforded extended electron-rich diferrocenyl bispyran 3, which was subsequently reversibly oxidized to diferrocenyl bispyrylium salt 4. This study constitutes a new system in which two ox/red sequences of different nature were separated by proton/deprotonation steps.