Single-crystal-to-single-crystal (SCSC) transformations have recently been found in some molecular magnets, which involve rearrangement or dynamic movement of molecular components of the crystals. Various stimuli such as guest removal, guest exchange, ligand exchange as well as redox reactions may induce SCSC transformations. To date, only a few molecular magnets are known to exhibit SCSC transformations, which often show high-dimensional robust structures. This review mainly focuses on magnetic complexes that are robust enough to experience SCSC transformations and show magnetic changes induced by solvents in due course. This contribution is organized according to the means of solvent treatment of molecular magnets, aiming at revealing magneto-structural correlation in such SCSC transformations.