Organic-inorganic hybrid perovskites are promising candidates for several optoelectronic devices, such as solar cells, light-emitting diodes, and photodetectors. Particularly, methylammonium lead iodide (MAPbI(3)) has been widely used as a light harvester in photovoltaic devices. However, MAPbI(3) has a fatal weakness in long-term stabilities of humidity and high temperature. In this work, we fabricated extremely stable quasi-2D structures of hybrid perovskite films by introducing methylammonium formate (MAF) and propylammonium formate (PAF) ionic liquids. We found that the perovskite films using the ionic liquids exhibited low-dimensional structures to contribute to improved environmental and thermal stabilities. We believe that this work elucidates the importance of solvent mediated crystal growing process and somehow guides the design of stable low-dimensional perovskites.