Fig. 11. TTA upconversion of C-1 with B-3 and B-3-Me H-bonding modules. 1-CBPEA was used as triplet acceptor. (a) Emission of B-3 and 1-CBPEA with increasing C-1 concentration; (b) emission of B-3-Me and 1-CBPEA with increasing C-1 concentration; (c) emission observed when 0 μL and 100 μL of hexafluoroisopropanol (HFIP) were added to a mixed solution of B-3, 1-CBPEA and 4 eq. C-1 to disrupt the H-bonding; (d) emission observed when 0 μL and 100 μL of HFIP were added to a mixed solution of B-3-Me, 1-CBPEA and 4 eq. C-1. Excitation was carried out with a 589 nm laser (4.4 mW, power density is 60 mW cm^–2), and a band-pass filter (470–570 nm) was used to suppress the scattered laser. The asterisks indicate the residual emission of the antenna. c[photosensitizers] = 1.0 × 10^–5 M. c[1-CBPEA] = 1.2 × 10^–4 M in deaerated toluene, 20 °C.