This dissertation discusses three studies on the Pd-catalyzed direct functionalization of aromatic C-H bonds. 1) Methods for direct amination are developed. 2) Mechanistic studies on direct arylation of benzene are performed by isolating the proposed intermediate (PtBu3)Pd(Ar)(OPiv) and studying its reactivity. 3) Detailed mechanistic studies on direct arylation of pyridine N-oxide are reported.