(A) HOMOs and LUMOs of Flav7 (1) and (5,6 and 8)-Flav7 (3–5) at M06–2X/6–31+G(d,p) level of theory. Polymethine chains were omitted for clarity. Explicit frontier molecular orbital information can be found in the SI. (B) Table of calculated λmax,calc,abs (nm) determined by theoretical HOMO-LUMO gap (eV). Δ is the difference between experimental and calculated λmax,abs.