To gain insight into the redox properties of 2, its chemical oxidation with an incremental addition of oxidant was performed, and ultraviolet-visible-near infrared (UV-Vis-NIR) absorption measurements were conducted. Neutral 2 exhibited a single absorption peak at 334 nm. With the addition of AgSbF6 as an oxidant, a new absorption peak appeared at around 520 nm (Figure ), and the peak intensity continuously increased for additions of up to three equiv. of AgSbF6. With more than three equiv. of the oxidant, insoluble solids started to precipitate, resulting in weaker absorption bands (Figure ). No other peak, except the one at 520 nm, was observed during the incremental addition of the oxidant. Electron paramagnetic resonance (EPR) studies showed that radical species of 2 were generated due to the oxidation (Figure ). The EPR hyperfine structures changed with the incremental addition of the oxidant, indicating the