Table 1. Photophysical Parameters for COUPY-Caged Model Compounds (3–8) and COUPY Dye 2a^a.

	absorption		emission
compound	λmax (nm)b	ε(λmax) (Μ–1 cm–1)c	λem (nm)d	Stokes shift (nm)e	ϕEmf
2a	546	46,300	603	57	0.22
3	557	38,000	619	62	0.10
4	556	35,200	629	73	0.08
5	555	35,000	630	75	0.08
6	570	59,400	634	64	0.08
7	560	27,600	613	53	0.06
8	563	42,900	619	56	0.10

^aAbsorption and emission spectra were recorded in a 1:1 (v/v) mixture of PBS buffer and ACN at 25 °C.

^bWavelength of the absorption maximum.

^cMolar absorption coefficient at λ_max.

^dWavelength of the emission maximum upon excitation at 20 nm below λ_max.

^eStokes shift.

^fFluorescence quantum yield.