A series of Ni(0) compounds supported by electronically similar N-heterocyclic carbene (NHC) ancillary ligands with a range of %V bur were used as catalysts for aryl C− H bond silylation, germylation, and stannylation. The NHC steric bulk strongly influenced the selectivity of C−H functionalization to give new carbon−heteroatom bonds versus alkene hydroarylation, despite little structural change in the resting state of the catalysts. Studies were performed by reacting C 6 F 5 H and H 2 CCHER 3 (ER 3 = SnBu 3 , GePh 3 , SiMe 3 ) using catalytic amounts of Ni(COD) 2 and NHC ligands IPr, IMes, IBn, and i Pr 2 Im. Catalytic C−H stannylation to give C 6 F 5 SnBu 3 was facile with all ligands. The catalytic C−H germylation reaction was more difficult than stannylation but was demonstrated using H 2 CCHGePh 3 to give C 6 F 5 GePh 3 for all but the largest NHC. The bulkiest NHC, IPr, gave a 96:4 ratio of the hydroarylation product C 6 F 5 CH 2 CH 2 GePh 3 versus C 6 F 5 GePh 3 . The C−H silylation reactions required the highest temperatures and gave selective silylation product C 6 F 5 SiMe 3 only for the smallest IBn and i Pr 2 Im NHC ligands. Using the larger IMes carbene resulted in a 66:34 mixture of silylation and hydroarylation products, and the largest NHC, IPr, gave exclusive conversion to the hydroarylation product, C 6 F 5 CH 2 CH 2 SiMe 3 . DFT calculations are provided that give insight into the mechanism and key reaction steps, such as the relative difficulty of the critical β-Sn, Ge, and Si elimination steps.