M(Pro₂-H)⁺ complexes were electrosprayed and isolated in an FTICR cell where their unimolecular chemistries and structures were explored using SORI-CID and IRMPD spectroscopy. These experiments were augmented by computational methods such as electronic structure, simulated annealing, and atoms in molecules (AIM) calculations. The unimolecular chemistries of the larger metal cation (Ca²⁺, Sr²⁺ and Ba²⁺) complexes predominantly involve loss of neutral proline whereas the complexes involving the smaller Mg²⁺ and transition metal dications tend to lose small neutral molecules such as water and carbon dioxide. Interestingly, all complexes involving transition metal dications except for Cu(Pro₂-H)⁺ lose H₂ upon collisional or IRMPD activation. IRMPD spectroscopy shows that the intact proline in the transition metal complexes and Cu(Pro₂-H)⁺ is predominantly canonical (charge solvated) while for the Ca²⁺, Sr²⁺, and Ba²⁺ complexes, proline is in its zwitterionic form. The IRMPD spectra for both Mg(Pro₂-H)⁺ and Mn(Pro₂-H)⁺ are concluded to have contributions from both charge-solvated and canonical structures.