The alpha 1-(Br-(CH2)(2)-NH3)(2)PbI4 hybrid perovskite undergoes a solid-state transformation, that is, the reaction between the organic cations and the perovskite layers to give the new hybrid perovskite (Br-(CH2)(2)-NH3)(2-x)(I-(CH2)(2)-NH3)(x)PbBrxI4-x, based on mixed halide inorganic layers. This transformation has been followed by a conventional powder X-ray diffraction system equipped with a super speed detector, and both solid-state C-13 NMR and ESI/MS measurements have been adopted in the estimation of the rate of halide substitution. The first reaction step leads to the special composition of x approximate to 1 (A phase), while the complete substitution is not achieved even at elevated temperature (x(max) approximate to 1.85 (B phase)). This unprecedented solid-state reaction between organic and inorganic components of a hybrid perovskite can be considered as a completely new strategy to achieve interesting hybrid perovskites.