We present a straightforward one-step process to access a range of novel p-diindolepyrazines via an unprecedented [n-Bu₄N][Fe(CO)₃(NO)] (TBA[Fe])-catalyzed intermolecular nitrogenative dimerization of various indole derivatives. Remarkably, tosylazide functions as a N1-synthon forming the central pyrazine unit that joins the two indole subunits. The catalytic transformation shows a good substrate scope, and the obtained products show interesting electronic properties.