Table 2. Photophysical properties of the BFPYOLs containing compounds (6a–m).

Comp. code	R 1	R 2	λ abs a (nm)	λ em b (nm)	PL intensity	Stokes shift (cm−1)	PLQYc (ΦPL)	Molar absorption coefficient (ε (M−1 cm−1))
6a	H	H	344	387	355	3229	0.41	14 100
6b	H	4-F	354	385	121	2274	nd	nd
6c	H	4-Cl	356	389	250	2382	0.48	7200
6d	H	4-Br	356	391	228	2514	0.30	13 300
6e	H	4-OCH3	353	393	416	2883	0.51	11 800
6f	H	4-CH3	355	388	314	2395	0.38	11 500
6g	H	4-Ph	352	385	875	2435	0.59	23 800
6h	H	Naph	353	383	798	2218	0.52	24 300
6i	H	4-NEt2	386	482	653	5159	0.88	16 800
6j	H	4-Pyrrolidine	386	488	813	5414	0.80	26 300
6k	H	4-Piperidine	375	488	476	6174	0.83	12 500
6l	H	4-Morpholine	369	480	695	6266	0.88	18 400
6m	H	4-Thiomorpholine	373	475	630	5757	0.88	14 700

^aAbsorbance with 20 μM.

^bEmission with 10 μM recorded for benzofuro[2,3-c]pyridinol-based compounds (6a–m) in solvent DMSO at 20 °C; excitation and emission slit width of 5; 5 nm, 600 V except 6g and 6h (570 V) for emission.

^cRelative PL quantum yield (Φ_PL) is calculated in DMSO solvent with reference quinine sulphate (reported Φ_PL = 0.54, calculated = 0.534 ± 0.04 at 360 nm in 0.1 M H₂SO₄).