The ground state absorption spectra of the ligand L and the metal complexes 1, 2 and 3 were recorded in dimethylformamide (DMF) and acetonitrile (ACN) at a concentration of 10 M as shown in Figure . The data for the absorption spectra are summarized in the table 1 and table -S4. Additionally, we recorded the absorption spectra of BiCl3, BiBr3, and BiI3 at the concentration of 10 M in DMF and ACN (Figure ).