A facile, green and economical preparation technique is critical for the cost-effective scale-up manufacture and optoelectronic device engineering of halide perovskites. Herein, we developed a viable solvent-free mechanochemical synthetic route to systematically prepare organic–inorganic hybrid perovskites. In this work, an enormous halide library comprising 16 zero-dimensional hybrid manganese halides with the formula of A_nMnX₄ (A = organic cations, X = Cl, Br, n =1, 2) was synthesized through an economically and environmentally friendly mechanical grinding solid-state reaction within a quite fast time of 40 s and 100% yield. Even without any crystallization process, these A_nMnX₄ display strong green light emissions with the highest photoluminescence quantum yield (PLQY) of 79.5%, which reaches up to the top rank of green-light-emitting halide perovskites. Moreover, the enormous structural library facilitates us to build up a direct correlation between intermolecular Mn⋯Mn distances and PLQY, which provides a feasibility of fine-tuning luminescence performance by reasonably managing organic species to tailor the Mn⋯Mn distance. This work not only paves a green assembly way of hybrid perovskite materials but also provides a generalized method to rationally optimize the luminescence performances of hybrid manganese halides, which is potentially extended to all emissive hybrid metal halides.