This review discusses the development of transition-metal-catalyzed methods for the arylation of carbon-hydrogen (C-H) bonds, focusing on palladium- and copper-catalyzed reactions. The authors address three major challenges in C-H bond functionalization: substrate specificity, the rarity of converting unactivated sp³ C-H bonds to C-C bonds, and the high cost of transition metals like palladium, rhodium, and ruthenium. They present a general method for directing-group-containing arene arylation using aryl iodides and palladium acetate, which successfully functionalizes anilides, benzamides, benzoic acids, benzylamines, and 2-substituted pyridine derivatives under similar conditions. A palladium-catalyzed auxiliary-assisted arylation method enables the β-arylation of carboxylic acid derivatives and γ-arylation of amine derivatives. Copper catalysis is used to mediate the arylation of acidic arene C-H bonds (pKa < 35 in DMSO), allowing the functionalization of electron-rich and electron-deficient heterocycles and electron-poor arenes with at least two electron-withdrawing groups. The reaction exhibits unusual regioselectivity, favoring the most hindered position. The authors also describe preliminary investigations into the mechanisms of these transformations, suggesting that other transition metals like iron, nickel, cobalt, and silver may also facilitate deprotonation/arylation reactions. The review highlights the importance of developing efficient, cost-effective, and general methods for C-H bond functionalization, which can lead to shorter synthetic routes and reduced environmental impact.This review discusses the development of transition-metal-catalyzed methods for the arylation of carbon-hydrogen (C-H) bonds, focusing on palladium- and copper-catalyzed reactions. The authors address three major challenges in C-H bond functionalization: substrate specificity, the rarity of converting unactivated sp³ C-H bonds to C-C bonds, and the high cost of transition metals like palladium, rhodium, and ruthenium. They present a general method for directing-group-containing arene arylation using aryl iodides and palladium acetate, which successfully functionalizes anilides, benzamides, benzoic acids, benzylamines, and 2-substituted pyridine derivatives under similar conditions. A palladium-catalyzed auxiliary-assisted arylation method enables the β-arylation of carboxylic acid derivatives and γ-arylation of amine derivatives. Copper catalysis is used to mediate the arylation of acidic arene C-H bonds (pKa < 35 in DMSO), allowing the functionalization of electron-rich and electron-deficient heterocycles and electron-poor arenes with at least two electron-withdrawing groups. The reaction exhibits unusual regioselectivity, favoring the most hindered position. The authors also describe preliminary investigations into the mechanisms of these transformations, suggesting that other transition metals like iron, nickel, cobalt, and silver may also facilitate deprotonation/arylation reactions. The review highlights the importance of developing efficient, cost-effective, and general methods for C-H bond functionalization, which can lead to shorter synthetic routes and reduced environmental impact.