We report a multinuclear solid-state (Na-13, K-39, Rb-87, Cs-133) NMR study of tetraphenylborate salts, M[BPh4] (M = Na, K, Rb, Cs). These compounds are isostructural in the solid state with the alkali metal ion surrounded by four phenyl groups resulting in strong cation-pi interactions. From analyses of solid-state NMR spectra obtained under stationary and magic-angle spinning (MAS) conditions at 11.75 and 21.15 T, we have obtained the quadrupole coupling constants, C-Q, and the chemical shift tensor parameters for the alkali metal ions in these compounds. We found that the observed quadrupole coupling constant for M+ in M[BPh4] is determined by a combination of nuclear quadrupole moment, Sternheimer antishielding factor, and unit cell dimensions. On the basis of a comparison between computed paramagnetic and diamagnetic contributions to the total chemical shielding values for commonly found cation-ligand interactions, we conclude that cation-pi interactions give rise to significantly lower paramagnetic shielding contributions than other cation-ligand interactions. As a result, highly negative chemical shifts are expected to be the NMR signature for cations interacting exclusively with pi systems.