Nα‐acylated β2,3‐3‐azapeptides, or α‐hydrazidopeptides, of different lengths were synthesized starting from a conformationally restricted imidazolidinone‐tethered monomer. The preferential conformations of the oligomers were investigated by NMR and CD spectroscopy, supported by computational analysis. The experimental data clearly confirmed the tendency of these α‐hydrazidopeptides to fold into a zig‐zag (Z8) 8‐helix conformation, whose stability is length‐dependent, stabilized by the C=O(i)···H–N(i + 2) and N(i)···H–N(i + 1) intramolecular H‐bonding pattern, as well as by non‐standard C=O···H‐C hydrogen bonds.