Rhodium(III) catalysis has enabled a plethora of oxidative C-H functionalizations, which predominantly employ stoichiometric amounts of toxic and/or expensive metal oxidants. In contrast, we herein describe the first electrochemical rhodium-catalyzed C-H activation that avoids hazardous chemical oxidants. Environmentally benign twofold C-H/C-H functionalizations were accomplished with weakly coordinating benzoic acids and benzamides, employing electricity as the terminal oxidant and generating H as the sole byproduct.

Nickela‐electrooxidative C−H alkoxylations with challenging secondary alcohols were accomplished in a fully dehydrogenative fashion, thereby avoiding stoichiometric chemical oxidants, with H2 as the only stoichiometric byproduct. The nickela‐electrocatalyzed oxygenation proved viable with various (hetero)arenes, including naturally occurring secondary alcohols, without racemization. Detailed mechanistic investigation, including DFT calculations and cyclovoltammetric studies of a well‐defined C−H activated nickel(III) intermediate, suggest an oxidation‐induced reductive elimination at nickel(III).

Chemoselective C−H arylations were accomplished through micellar catalysis by a versatile single‐component ruthenium catalyst. The strategy provided expedient access to C−H‐arylated ferrocenes with wide functional‐group tolerance and ample scope through weak chelation assistance. The sustainability of the C−H arylation was demonstrated by outstanding atom‐economy and recycling studies. Detailed computational studies provided support for a facile C−H activation through thioketone assistance.

Metal‐catalyzed chelation‐assisted C−H olefinations have emerged as powerful tools for the construction of functionalized alkenes. Herein, we describe the rhoda‐electrocatalyzed C−H activation/alkenylation of arenes. The olefinations of challenging electron‐poor benzamides were thus accomplished in a fully dehydrogenative fashion under electrochemical conditions, avoiding stoichiometric chemical oxidants, and with H2 as the only byproduct. This versatile alkenylation reaction also features broad substrate scope and used electricity as a green oxidant.

Electrochemical oxidative C−H/N−H activations with isocyanides have been realized with a versatile cobalt catalyst. The widely applicable cobalt catalysis manifold further enabled electrooxidative C−H/N−H carbonylations with carbon monoxide under ambient conditions. The C−H functionalizations were efficiently realized with ample scope and outstanding functional group tolerance in a user‐friendly undivided cell setup.