Thin films on ITO coated glass substrates were prepared by spin coating. 65 μL of a p(NDI-T2 P75) solution (10 mg/mL) were spin coated onto a cleaned ITO coated glass substrates at 1000 r.p.m.. A thin layer of epoxy glue was applied at the edges of the film to prevent delamination (5 minute setting, Loctite Epoxy). The p(NDI-T2 P75) film was then placed into a quartz cuvette (DLC-300-Q-20, Starna Cells) filled with 0.1 M KOH. The electrochemical measurements were completed in a three-electrode set-up with a PEEK-shrouded leakless Ag/AgCl reference (eDAQ) and a coiled Pt wire as the counter. The UV-vis measurements were completed with a Tungsten light source (HL-2000-LL, Ocean Optics) and a spectrometer (QE Pro, Ocean Optics) and the instruments were synchronized using a Matlab code.