In our previous work, we could monitor the protonation of the BT analogue BTDN, from CV in presence of an organic acid, salicylic acid . We therefore first looked into the CV of pristine PFBT polymer both for the washed and the commercial as-received polymer while dissolved in THF. The electrochemical behaviour of PFBT is very complex with many available redox states (Figure ). It is however clear that the reduced polymer reacts with acids in a solution (Figure