The crystal structure of the title compound, C11H7BrO3, has been deter
mined using 1549 observed reflections with I > 2.5 sigma(I). The couma
rin moiety is planar and makes a dihedral angle of 6.6(4)degrees with
the mean plane of the acetyl group attached to C(3). The molecules ado
pt the S-cis configuration in the crystal and are linked by weak C-H .
.. O interactions.