We illustrate here the high photocatalytic activity of
sustainable
lead-free metal halide nanocrystals (NCs), namely, Cs3Sb2Br9NCs, in the reduction ofp-substituted benzyl bromides in the absence of a cocatalyst. The
electronic properties of the benzyl bromide substituents and the substrate
affinity to the NC surface determine the selectivity in C–C
homocoupling under visible light irradiation. This photocatalyst can
be reused for at least three cycles and preserves its good performance
with a turnover number of ca. 105,000.