Singh, ManojManojSinghPourceau, GwladysGwladysPourceauQuéhon, LucieLucieQuéhonSauvage, FrédéricFrédéricSauvageBanerjee, RupakRupakBanerjee2026-01-122026-01-122025-11-0610.1002/smll.2025068942-s2.0-105016474672http://repository.iitgn.ac.in/handle/IITG2025/3381140964855Low-dimensional perovskites show great promise due to their stronger structural stability against external stressors, in particular, moisture. However, the alternance of organic and inorganic layers contributes to form a quantum-well structure leading to the bi-dimensional confinement of the carrier's transport, thus limiting the performances in solar-to-fuel conversion applications. To overcome this issue, the synthesis of the 1D vinylenedipyridine-based (4,4′-VDP)Pb<inf>2</inf>X<inf>6</inf> perovskite (X = Br, I), whose specificity is to combine pi-conjugated spacer and cation–pi interactions, is reported. The pi-conjugation electronically connects the inorganic layers, and the cation–pi interactions facilitate stability against water. As a result, exceptional structural and photostability in a large range of aqueous pH is demonstrated. Whereas (4,4′-VDP)Pb<inf>2</inf>Br<inf>6</inf> does not show photocatalytic activity toward hydrogen production due to misaligned band energy position with HBr, the iodide counterpart (4,4′-VDP)Pb<inf>2</inf>I<inf>6</inf> perovskite produces a substantial amount of hydrogen (1.81 mmol g⁻¹ after 24 h of photoreaction), without noble metal catalyst utilization and under standard AM 1.5 G illumination conditions.falsecation–pi interactions | hydrogen generation | hydrohalic acids | low-dimensional perovskites | photocatalysis | pi conjugationArticle161368296 November 20250e06894arArticle