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A series of original heteroleptic dirhodium(II) complexes (4 a–j) of formula [Rh2(OAc)3(L)], where L is a redox‐active ferrocenecarboxylate ligand, has been prepared. These dirhodium(II) complexes have been characterised by NMR, mass spectrometry and cyclic voltammetry. All complexes show a quasi‐reversible redox behaviour for the ferrocenyl unit. The latter can be selectively oxidised by [N(4‐C6H4Br)3]+BF4−. Four selected heteroleptic complexes 4 a, 4 b, 4 f and 4 i, have been evaluated as catalysts for the intramolecular decomposition of a diazo compound 5. The ratio between the aromatic substitution product 6 and the aliphatic C−H insertion product 7 increases (up to 19 % increase) when using the in situ generated oxidised form of the dirhodium(II) complexes (4 a+BF4− to 4 i+BF4−). This shows that the oxidation of the ferrocenecarboxylate ligand has an effect on the chemoselectivity of the dirhodium‐catalysed diazo decomposition, and thus that the electronic properties of a complex can be tuned without exchanging ligands. [ABSTRACT FROM AUTHOR]