Fluorine atom plays a very important role in pharmaceuticals, agricultural chemicals, and medical imaging and it has become one of the most popular area in organic chemistry. For example, in modern medicinal chemistry introducing fluorine atom could potentially improve absorption, metabolism and potency of drug candidates. As a result, methods that allow the selective and efficient formation of the carbon-fluorine bond are highly desirable. An evolving approach is the utilization of transition-metals to catalyze the nucleophilic substitution of fluoride ion. This thesis described several novel and efficient methods to generate allylic and benzylic C-F bonds using rhodium/iridium catalyst.