Table 1.

Radiative (k _r) and non‐radiative (k _nr) transition rates of each regioisomer in solution and colloidal suspensions (THF:H₂O=1:9).

	THF solution		Colloidal suspension[a]
	k r [106 s−1]	k nr [106 s−1]	k r [106 s−1]	k nr [106 s−1]
1,4‐isomer	25	76	24	30
9,10‐isomer[b]	50	250	53	109
1,5‐isomer	67	20	49	360
1,8‐isomer	48	20	31	170
2,6‐isomer	54	7.2	43	250

[a] Rate constants were calculated based on amplitude‐averaged lifetimes. [b] The N,N‐dipropylamine analogue of 9,10‐BPA was used because the Φ _fl of 9,10‐BPA (0.02) is too small to derive reliably accurate rate constants.