Diverse strategies allow for the synthesis of substituted azetidines, including [2+2]-cycloadditions, ring expansions, ring contractions and ring closures. In addition, we recently contributed to this field through manipulation of unsaturated analogs -2H-azetines -via Diels-Alder cycloadditions or hydrogenation reactions. Due to their ring strain, easily-accessible 1-azabicyclo[1.1.0]butanes (ABB) possess an interesting reactivity towards nucleophiles, representing therefore an interesting platform for further functionalizations. Given the high strain in C-N-C dihedral angles, ABB are strong nucleophiles and should readily react with electrophilic species. Following the pioneering work of Funke, the group of Nagao exploited the concept of strain-release on ABB with nucleophiles such as halogens and thiols, in the presence of N-trapping reagents like acyl-and tosyl chlorides (Scheme 1A). In 2016, Baran developed an efficient strain-release amination protocol based on the use of primary and secondary turbo-amides as nucleophiles, for the late-stage diversification of drug-like molecules. More recently, Gianatassio and co-workers exemplified the nucleophilic addition of Grignard reagents in the formation of the corresponding 3-alkylazetidines when using Boc2O, TsCl or acyl chlorides as electrophiles. 1,2-Boronate rearrangements also proved efficient for the substitution of azetidines at position 3 from ABB. Surprisingly, molecules as simple as 1,3-bisarylated azetidines are scarcely found in the literature, which certainly stems from the difficulty to access their structure efficiently and selectively. Despite efforts mentioned above, the introduction of aryl moieties at position 3 of ABB through strain-release remains undisclosed. With a general interest in 4-membered carbo-and heterocycles and their implication in drug discovery, we set out to establish a reliable method for the construction of such functionalized azetidine architectures. Our investigations started with the examination of the ringopening reactions of ABB with ex situ generated aryl-Grignard reagents. In previous reports, AAB were generated in THF by double cyclization, employing an excess of phenyl lithium as base for deprotonation. First experiments were performed following these conditions (PhLi, THF), revealing however the formation of several by-products. The expected product 3, obtained via nucleophilic addition of p-TolMgBr was only produced in low yields and could not be isolated from 4 and 5, generated by the nucleophilic additions of residual PhLi and THF-soluble LiBr, respectively.