The synthesis, characterization, and PGSE (H-1 and F-19) NMR diffusion studies on the cationic [(eta(6)-arene)Mn-(CO)(3)][X] (arene = anisole, 4-chloroanisole, and 1,3,5-trimethoxybenzene; X = BPh4 and BArF) are reported. The tetraphenyl borate complexes of anisole and 4-chloroanisole show surprisingly strong ion pairing in dichloromethane solution, whereas the BArF salts do not. H-1,H-1-NOESY data support this anion selectivity. In chloroform solution one finds the usual strong ion pairing for both anions. The solid-state structure of [(eta(6)-1,3,5-trimethoxybenzene)-Mn(CO)(3)][BPh4] has been determined. C-13 NMR and IR data for the new complexes are reported. The observed IR frequencies are higher for the BArF complexes than for the BPh4 complexes.