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An analysis of the intervalence charge-transfer (IVCT) band of (E)-4,4'-Bis{bis(4-methoxyphenyl)amino}stilbene (1) , which is narrow and asymmetric and exhibits only weak solvatochromism, indicates that 1(supper +) is a class-III or classII/III borderline mixed-valence(MV) species. The narrowness, asymmetry, and solvatochromism of the IVCT band of the 4,4'-bis(di-p-anisylamino)stilbene MV cation, (E)-4,4'-Bis{bis(4-methoxyphenyl)amino}stilbene(super +), indicates that this species falls into a similar regime of delocaliztion as bis(diarylamino)biphenyl cations.

Sonogashira coupling is used for preparing a chromophore in which zinc porphyrin donors are linked through their meso positions by ethynyl bridges to a bis(indolinylidenemethyl) squaraine core. The chromophore has displayed a two-photon absorption spectrum characterized by a peak cross section of 11000 GM and has also displayed a large cross section of >780 GM over a photon-wavelength window.

Stable extended bis(donor) squaraines that show extremely large [delta] at photon wavelengths of 1 [mu]m were synthesized. It was seen that a large third-order susceptibility and significant two-photon absorption were demonstrated in a film at telecommunication wavelengths.

A study is conducted which shows that extended D-A-D oligophenylenevinylenes show large two-photon absorption (TPA) cross sections in a wide wavelength range and peak cross sections up to 5300 GM. The findings indicate that relatively small changes in molecular structure can lead to large effects on the optical properties in this class material.

Efficient single-photon and multiphoton induced fluorescence resonance energy transfer (FRET) between donor two-photon absorbing chromophore (TPAC) moieties and a nile red acceptor chromophore in the novel dendrimers is demonstrated. A synthesis of these dendritic energy-harvesting systems and the results of the relevant absorption, single-photon, and multiphoton fluorescence experiments are detailed.

Study is presented to show that chromophore-metal particle assembly has impressive two-photon properties, and the level of interaction between chromophores may be related to formation of specific geometric domains on the metal surface. The evidence for ultrafast energy migration is seen in this chromophore shell-metal nanoparticles system, which is of potential interest for light harvesting and sensing applications.

A novel bichromophoric system that is capable of undergoing efficient fluorescence resonance energy transfer (FRET) following either two-photon or single photon excitation is presented. The bichronophoric system uses FRET to show that it is possible to utilize high-intensity infrared light to activate molecules.