Hydrogen peroxide is one of the most important molecules in chemical signaling in living organisms. Because of this, its sensing is indispensable for the diagnosis of many diseases. Among the materials used for the detection and quantification of H 2 O 2 , Prussian Blue (PB) has been highlighted due to its performance. Therefore, the search for alternatives or the improvement of PB performance is a challenge. In this context, our motivation was to evaluate how the ligand N-methylpyrazinium affects the structure and reactivity of Prussian Blue films [a]