The interaction of the nitric oxide ions NO+ and NO- with benzene (C6H6) and the aromatic R-groups of the amino acids phenylalanine (Phe), tyrosine (Tyr), histidine (His), and tryptophan (Trp) have been examined using the DFT method B3LYP and the conventional electron correlation method MP2. In particular, the structures and complexation energies of the resulting half-sandwich Ar center dot center dot center dot NO+/- and sandwich [Ar center dot center dot center dot NO center dot center dot center dot Ar](+/-) complexes have been considered. For the Ar center dot center dot center dot NO+ complexes, the presence of an electron rich heteroatom within or attached to the ring is found to not preclude the cation center dot center dot center dot pi bound complex from being the most stable. Furthermore, unlike the anionic complexes, the pi center dot center dot center dot cation center dot center dot center dot pi ([Ar center dot center dot center dot NO center dot center dot center dot Ar](+)) complexes do not correspond to a "doubling" of the parent half-sandwich.