2D organic–inorganic lead iodide perovskites (HO(CH₂)₄NH₃)₂(MA)_n−1Pb_nI_3n+1 (n = 1, 2, 3, and 4) were prepared and showed enhanced UV stability due to the additional inner hydrogen bonds between adjacent spacer cations, compared with the counterpart (CH₃(CH₂)₃NH₃)₂PbI₄ without the additional inner hydrogen bonds. The hydrogen bonds were formed between the hydroxyl groups of the organic spacer cations BA–OH⁺ and were demonstrated by the ¹H NMR chemical shift of the active hydrogen of the spacer's hydroxyl groups. The 2D (HO(CH₂)₄NH₃)₂(MA)_n−1Pb_nI_3n+1 perovskites remained stable after 10 days of UV radiation, while the (CH₃(CH₂)₃NH₃)₂PbI₄ perovskites decomposed after 3 days of UV radiation, as indicated by the XRD results.