Five aromatic hydrocarbon-TCNE complexes are dispersed in sodium chloride pellets and subjected to high pressures (0–25 kbar). The charge transfer absorption is enhanced and displaced toward lower energies at the highest pressure. An exception is the crystalline complex HMB-TCNE which exhibits a blue shift at the highest pressure. The doublet structure in both charge transfer bands of naphthalene-TCNE can be observed at 1 atm and at higher pressures. The importance of the relative sizes of donor and acceptor in environmental interactions are discussed.