Aza‐Nazarov reactions starting from 1‐azapenta‐1,4‐dien‐3‐ones offer an attractive route to five‐membered nitrogen heterocycles such as N‐substituted pyrroles. It has now been discovered that N‐indolinylhydrazone‐derived 1‐azapenta‐1,4‐dien‐3‐one 9a gives different products under conditions of varying acidity. Under strongly acidic conditions (2 equiv. of triflic acid, dilute solution, “electrophilic” conditions) it simply undergoes an aza‐Nazarov reaction to give N‐indolinylpyrrole 15a after workup with acetic anhydride. If, however, a large excess of triflic acid is used (7–10 equiv., concentrated solution, “superelectrophilic” conditions), 9a has been found to undergo an aza‐Nazarov reaction cascade followed by N–N bond cleavage to give NH‐pyrrole 10a and acetylated indole 8 as the final products (after workup with acetic anhydride). High‐level quantum chemical calculations were used to explain this acid‐concentration‐dependent reaction cascade. The formation of the reaction products can be explained in terms of an electrocyclization reaction of the protonated starting material 9a and a subsequent N–N bond cleavage reaction involving either mono‐ or dicationic species under strongly acidic conditions.