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We have developed a synthetic strategy for prepareation dipolar NLO chromophores with an interposed conjugated tetraene segment which contains all but four of the methine groups iscorporated into a double annulated ring. The configuration-locking approch furnishes NLO chromophores possessing enhanced thermal stability compared with their simple tetraaene analogues. The data from UV-vis spectroscopy reveal that the rigidity of the annulated rings do not diminish the planarity and the electron delocaliation efficiency of the polenic chain.
In addition, we have synthesized a NLO chromophone with all the methine groups in the tetraene segment incorporated into a rigidified triple annulated ring. This kind of approch yields the NLO chromophore with even better thermal stability.
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