Abstract2‐Vinylindole (1a) and its donor‐ and acceptor‐substituted (E)‐derivatives1b–ereact highly locoselectively with dimethyl 1,2,4,5‐tetrazine‐3,6‐dicarboxylate (3) to form the novel (indol‐2‐yl)‐1,4‐dihydropyridazines4aand7as well as the heterocyclic annellated pyridazines4b,5, and6. The reactions of the structurally related 3‐vinylindoles2a–ewith3also gave rise to new indol‐3‐ylpyridazines8,9, and10. The locoselectivities of theseDiels‐Alderreactions were co