A mechanically induced solid-state reaction method for the synthesis of organic-inorganic hybrid perovskites, such as methylammonium lead iodide (CH3NH3PbI3) is reported. The perovskites were synthesized both in bulk and Al2O3-supported forms. The phase- and structural-formation mechanisms of such perovskites are also investigated. The experiments suggest that diffusion of PbI2 into CH3NH3I crystals is a rate-limiting step of the reaction process. It is also shown that water (humidity) significantly influences the reaction kinetics. UV-Vis-NIR absorption and photoluminescence spectroscopies indicate that the band edge and emission characteristics of the as-fabricated materials strongly depend on their particle size.