In order to better understand star formation in galaxies, it is important to have a firm grasp on the physics of the ISM. In particular, the role of magnetic fields in controlling the large-scale dynamics of the ISM and molecular cloud formation, is still unclear. In 2020, Tress et al presented high-resolution, three-dimensional AREPO simulations inspired by the M51 galaxy, and in this project, we will be running magnetised versions of these hydrodynamic simulations to investigate how this changes the dynamics of the ISM. The initial goals of this work are threefold; firstly to find if magnetic fields significantly change the properties of molecular clouds, secondly to determine if magnetic fields change the star formation history of molecular clouds, and thirdly to discern what observational signatures of magnetic fields on the cloud formation process can be detected.