Well-defined fluorene oligomers (n = 1 to 6) were prepared step by step using Suzuki and Yamamoto couplings, while absorption and photoluminescence properties evidenced very large dipolar coupling interactions between fluorene moieties.

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We describe the synthesis and nonlinear absorption properties of triarylamine derivatives. Six molecules were synthesised by using a double Ullmann coupling procedure. UV-Vis absorption spectra show the excellent transparency of these triarylamine derivatives in the visible range (l cut-off ¡ 420 nm). Nonlinear absorption measurements show a broadband nonlinear absorption range extending between 450-650 nm with an optimised efficiency for a planar conjugated system (fluorene, molecule 10) or a hindered donor group (molecule 12). These data were interpreted by means of a two step three-photon absorption scheme: a TPA process followed by an S 1 AS n ESA step; the product of both spectra is qualitatively in good agreement with nonlinear absorption spectra, leading to different molecular engineering approaches for optimisation of these features in the visible range through TPA and/or ESA properties.