Self-supported electrochemical methoxylation and acetoxylation of various organic molecules were carried out using a thin-layer flow cell without intentionally added supporting electrolyte. The thin-layer flow cell employed in this work had a simple geometry with working and auxiliary electrodes directly facing each other with <mml:math display="inline"><mml:mrow><mml:mn>80</mml:mn><mml:mspace width="0.3em"></mml:mspace><mml:mi mathvariant="normal">μ</mml:mi><mml:mi mathvariant="normal">m</mml:mi></mml:mrow></mml:math>80μm distance. Controlling factors for these kinds of self-supported electrochemical methoxylation and acetoxylation, such as the electrode material, the current density, and the flow rate were optimized to allow moderate to high yields of the corresponding methoxylated and acetoxylated products to be achieved in single flow-through operations.