This review discusses the transition metal-catalyzed decarboxylative allylation and benzylolation reactions, focusing on homogeneous catalysis. Decarboxylative coupling reactions, which use decarboxylative metathesis to generate organometallic intermediates, offer several advantages over traditional cross-coupling methods, including the use of inexpensive and readily available carboxylic acid derivatives, mild reaction conditions, and environmentally benign byproducts (CO₂). The review highlights the scope and chemoselectivity of decarboxylative allylation, including the regioselective generation of enolates and the ability to form both nucleophile and electrophile in situ. It also covers the development of asymmetric decarboxylative allylation, including the control of stereochemistry at the β-carbon and α-carbon, and the use of alternative catalysts such as molybdenum, nickel, rhodium, and iridium. The mechanisms of decarboxylative allylation are discussed, emphasizing the ionization/oxidative addition step and the role of different ligands in influencing the reaction pathways.This review discusses the transition metal-catalyzed decarboxylative allylation and benzylolation reactions, focusing on homogeneous catalysis. Decarboxylative coupling reactions, which use decarboxylative metathesis to generate organometallic intermediates, offer several advantages over traditional cross-coupling methods, including the use of inexpensive and readily available carboxylic acid derivatives, mild reaction conditions, and environmentally benign byproducts (CO₂). The review highlights the scope and chemoselectivity of decarboxylative allylation, including the regioselective generation of enolates and the ability to form both nucleophile and electrophile in situ. It also covers the development of asymmetric decarboxylative allylation, including the control of stereochemistry at the β-carbon and α-carbon, and the use of alternative catalysts such as molybdenum, nickel, rhodium, and iridium. The mechanisms of decarboxylative allylation are discussed, emphasizing the ionization/oxidative addition step and the role of different ligands in influencing the reaction pathways.