Figure 2.

Steady-state normalized absorption (dashed line) and emission (solid line) spectra of 4a (∗), 4a′, and ICG (#) in DMSO (see footnote (20)). Absorption/emission maxima: 4a: 757 nm/779 nm; 4a′: 824 nm/840 nm; and ICG: 794 nm/831 nm. Fluorescence emission was excited at 690 nm.