A bromo-substituted chiral smectic liquid crystal was synthesized for the purpose of the study on the sub-phases of the chiral smectic C* (SmC* variants) using resonant X-ray scattering. The introduction of a bromo atom was found to have a significant effect on the phase sequence. The bromo-substituted compound exhibited enantiotropic smectic phases in a wide temperature range of more than 130 K, in which at least five SmC* variants appeared below the smectic A phase. On the basis of the electro-optic and dielectric measurements, each SmC* variant was identified and assigned, and the structures of which were investigated by resonant X-ray scattering.