Large aggregated parent ions, for example, C(8)A(7)(+) (C = cation and A = anion), have been observed within some protic ionic liquids (PILs) using electrospray ionization mass spectrometry (ESI-MS). We have shown that the formation and size of aggregates is dependent on the nature of the anion and cation. Solvent structuring in select PILs through aggregation can contribute to their classification as "poor ionic liquids" and can also strongly influence the entropic component to the free energy of amphiphile self-assembly in select PILs.