Lowest energy transitions with a 9-borafluorene character calculated at the CAM-B3LYP/6-31+G(d,p) level of theory for 2b in the gas phase and for 3a and 3b in n-hexane.

Compound	State	E [eV]	λ [nm]	f	Symmetry	Major contributions	Λ
2b	S1 ← S0	3.07	403	0.0016	A	HOMO → LUMO (66%)	0.61
						H−1 → L+1 (30%)
	S2 ← S0	3.10	401	0.0001	A	H−1 → LUMO (62%)	0.61
						HOMO → L+1 (35%)
	S3 ← S0	3.97	313	0.1529	A	H−2 → LUMO (83%)	0.61
3a	S1 ← S0	2.90	427	0.0021	A	H−1 → LUMO (68%)	0.51
						HOMO → LUMO (25%)
	S2 ← S0	3.75	331	0.059	A	HOMO → LUMO (52%)	0.41
						H−1 → LUMO (16%)
						HOMO → L+1 (12%)
	S5 ← S0	4.32	287	0.4836	A	H−4 → LUMO (39%)	0.63
						H−1 → L+1 (30%)
						HOMO → L+1 (10%)
	S15 ← S0	5.23	237	0.4388	A	H−7 → LUMO (13%)	0.62
						H−6 → LUMO (11%)
						H−4 → L+1 (35%)
3b	S1 ← S0	2.88	430	0.0031	A	HOMO → LUMO (91%)	0.51
	S2 ← S0	3.53	351	0.0091	A	H−2 → LUMO (89%)	0.60
	S3 ← S0	3.69	336	0.0738	A	H−1 → LUMO (62%)	0.34
						H−3 → LUMO (16%)
	S7 ← S0	4.37	284	0.4162	A	H−6 → LUMO (32%)	0.62
						H−4 → LUMO (14%)
						HOMO → L+1 (21%)
	S12 ← S0	4.98	249	0.5429	A	H−8 → LUMO (10%)	0.55
						H−2 → L+1 (39%)
						H−1 → L+1 (12%)