Here, we report an electrophilic azetidinylation strategy that enables modular access to a library of functionalized 3-aryl azetidines based on the underexplored reagents, azetidinyl trichloroacetimidates (ATAs) (Figure 1C, this work). Under simple activation conditions, ATAs are able to efficiently couple with more than 20 classes of nucleophiles, including fundamental building blocks and complex approved drugs. This straightforward protocol can also simplify the synthesis of advanced intermediates toward bioactive compounds and basic structures holding high commercial value, as well as streamline the access to azetidine analogues for drug molecules.