New synthetic strategies towards conjugated NLO-phores and fluorophores

Thermally stable push-pull chromophores built around thiophene-based rr-conjugating spacers rigidified by covalent bridging are described. We show that rigidification of the spacer produces a huge enhancement of the quadratic nonlinear susceptibility which reaches values among the highest known to date. In addition, we show that introduction of proquinoid accepters as building blocks for the design of conjugated fluorophores leads to new systems combining tunable emission wavelength at constant geometry, emission quantum yields close to unity, low oxidation potential and high electron affinity.