A cobalt-catalyzed ortho-C−H benzylation reaction of pivalophenone N−H imines with benzyl phosphates is reported. The reaction is promoted at room temperature by a ternary catalytic system comprising Co(acac)3, a pyridylphosphine ligand, and a Grignard reagent and tolerates a series of substituted pivalophenone imines and benzyl phosphates to afford various diarylmethane derivatives in moderate yields.