Dehydrogenative coupling (DC) reactions are of importance for the construction of new carbon‐element bonds in synthetic organic chemistry. In this work, we report on the synthesis and characterization of several redox‐active guanidino‐functionalized aromatic molecules (GFAs) for use in DC (C‐C and C‐O) reactions. In a systematic approach, we first characterize the new DC reagents in all relevant redox and protonation states, and compare their performance in competitive test proton‐coupled electron transfer (PCET) reactions. Then, their use in four different DC reactions with different mechanisms is evaluated.