“…Because of the small differences in Rf values of the mono-, di-, tri-, and tetra-substituted compounds, further purification was performed via preparative (recycling) size exclusion chromatography (prep-SEC) to obtain BODIPYs 5a-f (and 5H) in pure form. S7 1,7-Dimethyl-3,5-di(4-(9,9-dimethyl-9,10-dihydroacridin-10-yl)styryl)-8-mesityl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (5a) 10 : Obtained according to the general Knoevenagel-type procedure using 1,3,5,7-tetramethyl-8-mesityl-BODIPY 2 (36.6 mg, 0.1 mmol) and 4-(9,9-dimethyl-9,10-dihydroacridin-10-yl)benzaldehyde (4a) (125.4 mg, 0.4 mmol). The crude product was purified by column chromatography (dichloromethane:hexanes, 30:70), followed by prep-SEC, affording 5a as a dark blue solid with red metallic luster (63.4 mg, 66%).…”