  Molecular magnetism aims to design materials with unique properties at the
molecular level, focusing on the systematic synthesis of new chemical
compounds. In this paper, we propose an alternative route to engineer molecular
magnetic materials through plasma irradiation. Our research indicates that the
long-range magnetic order temperature in the three-dimensional
$\mathrm{\{[Mn^{II}(H_2O)_2]_2[Nb^{IV}(CN)_8]\cdot 4H_2O\}_n}$ molecular
ferrimagnet increases by 20 K after plasma treatment. The core structure of the
compound does not reveal significant changes after plasma processing, as
confirmed by the X-ray powder diffraction analysis. The observed results are
attributed to the release of crystallized water molecules. The described
procedure can serve as a viable approach to altering the magnetic properties of
the molecular systems.
