Hydrocarbons are not only the major constituents of oil and natural gas, but also the most abundant, low-cost stock for functionalized organic chemicals. Because of their chemical inertness, the transformation of the hydrocarbons to value-added products requires the activation of thermodynamically stable C-H and C-C bonds. Metal-mediated bond activation circumvents this problem by stimulating inert hydrocarbons to react with other molecules. Metal-Hydrocarbon radicals formed in the entrance channel and subsequent steps are transient and reactive and play essential roles in such activation reactions. In our work, metal-hydrocarbon reactions are carried out in a pulsed supersonic molecular beam source; reaction intermediates and products are identified by time-of-flight mass spectrometry and investigated by pulsed-field-ionization zero-electron-kinetic-energy, mass-analyzed threshold ionization, IR-UV photoionization, and electron velocity-map imaging spectroscopies. In this talk, we will discuss metal-hydrocarbon radicals formed by metal adsorption on aromatic surfaces and by metal-mediated dehydrogenation, C-C bond breakage and coupling, and cyclo-oligomerization of small alkenes and alkynes. The discussion will include the bonding and structures, electronic states and energies, and formation mechanisms of the radicals.