A tridentate, NNC-tb (where NNC-tb = 2-(pyridin-2-yl)benzo[h]quinoline) ligated IrIII complex (NNC-tb)Ir(Ph)(4-MePy)(TFA), 11 along with analogues are very active for CH activation as evidenced by rapid catalytic H/D exchange between benzene and trifluoroacetic acid – d1 (DTFA).