The origin of chiroptical activity in chiral perovskites, promising materials for spintronic and polarization-based optoelectronic devices, is investigated. Nano-confined growth of chiral perovskites (MBA₂PbI₄(₁₋ₓ)Br₄ₓ) reveals that asymmetric hydrogen-bonding between chiral molecular spacers and the inorganic framework is key to promoting chiroptical activity. Nanoconfined perovskites show significant asymmetry (absorption dissymmetry of 2.0 × 10⁻³ and anisotropy factor of photoluminescence of 6.4 × 10⁻²). Electronic interactions between building blocks are crucial for chirality transfer in hybrid materials.
