Figure 5.

Normalized UV/Vis/NIR absorption spectra of the a) cations and b) dications of 4T‐PBI (black), 5T‐PBI ^[16] (red), 6T‐PBI (blue) and 7T‐PBI (green), respectively. All measurements were carried out in CH₂Cl₂ solutions with Bu₄NPF₆ at room temperature (c ₀=10⁻⁴ M). c) LUMO and d) HOMO of 4T‐PBI based on the molecular geometry received from X‐ray analysis. The hexyl chains were omitted for clarity. The quantum mechanics calculations were carried out on the level of B3LYP density functional with the 6–31G(d) basis set as implemented in Gaussian 16.