Carbocations are important reactive intermediates that are invoked in many chemical transformations. These species are usually of the tricoordinated variety. Conversely, dicoordinated carbocations are rarely relevant in practical chemical processes due to their high energy and energetically challenging formation. In this talk I will discuss our recent efforts to utilize phenyl and vinyl carbocations in C–H functionalization reactions. We will describe how these high-energy dicoordinated carbocations can be generated under mild conditions and utilized in selective C–C bond forming reactions. Moreover, we will discuss our efforts to understand the mechanism of these reactions through computational chemistry, kinetics, electron microscopy, and isotopic labeling studies.