This report describes a general method for the one‐pot direct N‐acylation of N‐heterocycles using our previously developed 4‐(N,N‐dimethylamino)pyridine N‐oxide (DMAPO)/di‐tert‐butyl dicarbonate (Boc2O) system. This system enables one‐pot N‐acylation reactions to provide bulky N‐acyl heterocycles starting from a wide variety of less nucleophilic N‐heterocycles and sterically hindered α‐fully substituted carboxylic acids in high yields. Moreover, this one‐pot method does not involve pre‐activation of substrates. The protocol has been successfully extended to one‐pot N‐acylation of 7‐azaindoles.