SummaryToday's society has an ever‐increasing demand for smaller‐scale, lower‐energy‐consuming, cheaper, and faster computing and digital signal processing systems. Photon‐coupled, fluorescent photoswitchable protein‐based architectures are promising candidates for the fulfillment of these requirements. In order to properly design digital circuits based on the aforementioned building blocks, an efficient simulation procedure is needed. We present a simple, differential equation‐based model, suitable for the design and simulation of such structures. It characterizes the radiation‐induced switching, the form‐dependent fluorescence, and the effect of photon coupling in a fast and efficient manner. The applicability of the model is demonstrated through simulations of the OR and NOR logic gates consisting of readily available, fluorescent photoswitchable proteins. It can be a potential design tool for future molecular logic circuitry based on such molecules.