Cross-dehydrogenative couplings (CDCs) have become one of the most straightforward protocols in the C-H bond functionalizations, showing step- and atom-efficiency without need of pre-functionalization of substrates and reactants. However, catalytic C-H amination procedures based on the CDC strategy by employing amine reactants are considered to be challenging mainly due to the highly nucleophilic character of parent amines to inhibit the catalytic turnovers and the difficulty in optimizing proper oxidative conditions. In spite of these concerns, recent efforts have led to notable advances in the C-H amination procedures, particularly in the intermolecular reaction system. In this thesis, we address the development of the transition-metal-mediated direct C-H amination of arenes with anilines, alkylamines and even ammonia. The reactions do not require pre-functionalization of the amine coupling partners. Thus, these C-N bond formation represent the unique examples that is compatible with external oxidants to afford aminated products. Mechanistic details, such as the isolation and characterization of key intermediates are also discussed.