Photoelectrochemical　(PEC)　devices　hold　huge　potential　to　convert　solar　energy　into　chemical　energy.　However,　the　high　cost　of　raw　materials　and　film　processing　has　hindered　its　practical　use.　In　this　study,　we　attempt　to　tackle　this　issue　by　fabricating　straightforward　semiconducting　polymer　films.　These　films　function　as　photoanodes　for　various　oxidation　reactions,　including　water　oxidation　and　oxidative　organosynthesis.　The　structures　of　the　polymer　were　assessed　by　incorporating　electron-rich　and　electron-deficient　co-monomers　into　dibenzo[b,d]thiophene　sulfone　materials.　Furthermore,　to　gain　comprehensive　insight　into　the　performance,　we　conducted　both　steady-state　and　in　operando　investigations,　revealing　that　the　active　site　on　the　polymer　surface　determines　the　rate　of　the　conversion　process.　This　study　marks　a　significant　stride　towards　leveraging　economically　viable　semiconductors　in　PEC　systems　for　efficient　solar-to-chemical　conversions.　It　addresses　the　challenges　of　high　material　costs　and　complex　film　processing,　paving　the　way　for　the　scaled-up　application　of　this　burgeoning　technology.　©　2024　The　Royal　Society　of　Chemistry.