This work deals with the first theoretical study of structural, electronic, and optical properties of CsBrF4 ternary compound by using first-principle calculations. The calculated structural parameters and atomic positions are in accordance with the experimental ones declared in the literature. The obtained electronic properties signalize that this compound is a semiconductor material with a direct energy band gap. According to the investigated optical properties, the vast optical absorption range in the ultraviolet region indicates that CsBrF4 semiconductor could be useful for specific applications in ultraviolet optoelectronic devices; consequently, this theoretical study is the potential to support future experimental research.