Herein, we present the first rotational study of the AlaAla dipeptide, brought into the gas phase by laser ablation. Two different structures have been unveiled in the isolated environment of a supersonic expansion by Fourier transform microwave spectroscopy. These structures have been identified through their rotational and ¹⁴N quadrupole coupling constants. The flexibility of the –NH₂ and –COOH ends allows the formation of strong intramolecular interactions giving rise to five- and seven-membered ring configurations.