Table 2. Photophysical Data of All of the D−π–A Compounds IK-(3–9).

compound IK-	solvent	λmax (nm)	εa(M–1 cm–1)	λem (nm)	Φemb (%)	Δν̅c (cm–1)
3	toluene	398	39 473	460	21.5	3836
	DCM	391	28 947	493	30.73	5292
	MeCN	399	34 210	507	58.96	5339
	DMF	405	44 736	562	81.66	6898
4	toluene	402	26 000	490	78.34	4467
	DCM	403	14 000	521	74.14	5620
	MeCN	404	26 000	537	38.37	6131
	DMF	412	16 000	559	54.72	6382
5	toluene	417	11 363	492	31.08	3655
	DCM	419	20 361	527	27.96	4891
	MeCN	413	25 000	548	50.33	5965
	DMF	426	27 272	590	53.18	6525
6	toluene	415	20 000	635	32.52	8348
	DCM	422	8333	627	46.83	7748
	MeCN	413	20 000	650	62.64	8829
	DMF	421	26 666	722	85.92	9902
7	toluene	424	20 833	621	26.69	7481
	DCM	424	27 083	618	38.42	7403
	MeCN	413		674	45.16	9377
	DMF	419	25 000	714	56.48	9861
8	toluene	437	10 723	635	34.82	7135
	DCM	436	17 426	659	45.25	7761
	MeCN	433		702	16.36	8849
	DMF	442	14 745	723	67.78	8843
9	toluene	449	10 294	635	34.81	6523
	DCM	446	11 764	676	46.16	7624
	MeCN	442		712	18.92	8580
	DMF	451	8823	723	76.78	8341

^aε was measured in toluene, DCM, MeCN, and DMF solution, but the case where no data are reported is due to low solubility.

^bFluorescence relative quantum yield of compounds IK-(3–9) was measured by using fluorescein (in 0.1 N NaOH in EtOH) as the reference (Φ_em = 0.79).

^cStokes shift Δν̅ = ν̅_abs – ν̅_em.