Abstract Direct CO 2 electroreduction to valuable chemicals is critical for carbon neutrality, while its main products are limited to simple C 1 /C 2 compounds, and traditionally, the anodic O 2 byproduct is not utilized. We herein report a tandem electrothermo‐catalytic system that fully utilizes both cathodic (i.e., CO) and anodic (i.e., O 2 ) products during overall CO 2 electrolysis to produce valuable organic amides from arylboronic acids and amines in a separate chemical reactor, following the Pd(II)‐catalyzed oxidative aminocarbonylation mechanism. Hexamethylenetetramine (HMT)‐incorporated silver and nickel hydroxide carbonate electrocatalysts were prepared for efficient coproduction of CO and O 2 with Faradaic efficiencies of 99.3 % and 100 %, respectively. Systematic experiments, operando attenuated total reflection surface‐enhanced Fourier transform infrared spectroscopy characterizations and theoretical studies reveal that HMT promotes *CO 2 hydrogenation/*CO desorption for accelerated CO 2 ‐to‐CO conversion, and O 2 inhibits reductive deactivation of the Pd(II) catalyst for enhanced oxidative aminocarbonylation, collectively leading to efficient synthesis of 10 organic amides with high yields of above 81 %. This work demonstrates the effectiveness of a tandem electrothermo‐catalytic strategy for economically attractive CO 2 conversion and amide synthesis, representing a new avenue to explore the full potential of CO 2 utilization.