Photophysical properties of the studied model compounds in solution phase^a.

Compound	λ 1PA b (nm)	ε (M−1 cm−1)	λ Em c (nm)	Φ F d	δ 2,max e (GM)	λ 2PA (nm)	δ 3,max f (10−80 cm6 s2)	λ 3PA (nm)
1	312	7.9 × 104	498	0.51	970	750	50	1280
	351	7.7 × 104
	428	6.1 × 104
2	308	1.3 × 105	499	0.57	2120	750	85	1280
	359	1.5 × 105
	439	1.4 × 105

^aSample solutions for linear and two-photon-related measurements were prepared in toluene whereas those for three-photon-related measurements were prepared in toluene-d₈.

^bLinear (one-photon) absorption maxima.

^cOne-photon-induced fluorescence emission maxima.

^dFluorescence quantum efficiency.

^eMaxima of two-photon absorption at λ^2PA_max; 1 GM = 1 × 10⁻⁵⁰ cm⁴ s/photon-molecule.

^fMaxima of three-photon absorption at λ^3PA_max.