The mode of coordination of 4-cyanophenylacetonitrile to silver ion in propylene carbonate and in nitromethane has been investigated by infrared spectrophotometry. In propylene carbonate, aromatic nitrile coordination is the only mode of nitrile coordination to silver ion; in nitromethane, it constitutes one-half of the nitrile coordination of silver ion. The results are explained in terms of the relative stability of aliphatic nitrile versus aromatic nitrile complexes of silver ion in the two solvents and of the compatibility of the aromatic nitrile and aliphatic nitrile coordinated 4-cyanophenylacetonitrile complexes with the solvent.