4-Bromopyrazole is a pyrazole derivative. It is reported to react with titanium tetrachloride to afford binary adducts. Mutagenicity of 4-bromopyrazole has been tested using the L-arabinose forward mutation assay of Salmonella typhimurium. It is reported to inhibit the oxidative phosphorylation, the ATP-32P exchange reaction, and energy dependent and independent calcium uptake. 4-Bromopyrazole is a heteroaryl halide and its cyanation in the presence of palladium catalysts has been reported.