In summary, we have developed a very efficient procedure for the 1,3-bis-arylation of azetidines, advantage of in situ generated reactive strained aza-bicyclobutanes. Unprecedented arylation at position 3 was performed with arylmagnesium reagents, adapting the solvent system to avoid undesired products, and demonstrating the high tolerance of the method for functional groups. Simple and versatile C-N bond formation strategies were applied in a single-pot sequence, allowing the design of a vast library of building blocks, including analogs of drug compounds, taking a step further towards the challenging implementation of rigid sp 3 -rich scaffolds in drug-discovery programs.