Abstract: Organic electronic devices are enabled by working electrodes. These are typically glass substrates coated with conductive ITO. These solid substrates are typically used for device operation by enabling charge mobility and for structurally supporting the device components. It will be shown that the working electrode can be engaged to prepare electroactive layers. Post-deposition reactions of active layers will additionally be illustrated. It will be shown that patterning and property modification are possible such as color, emission, and electrochemistry by post-deposition reactions, in part by taking advantage of reversible bonds.