This work demonstrates an exotic role of CH2Cl2 in a formation of stable phase of highly crystalline CH3NH3PbI3 perovskite, on a bulk scale. In the first method, a partially-reacted product obtained after co-grinding of precursors viz. CH3NH3I and Pbl(2) was sonicated in CH2Cl2 to form pure phase of CH3NH3PbI3. In second method, the precursors in gamma-Butyrolactone were treated with CH2Cl2 to form crystalline and phase-pure CH3NH3PbI3. X-ray Diffraction analysis confirmed the formation of stable and highly crystalline tetragonal phase of CH3NH3PbI3 perovskite having space group I4cm. Well-defined rhombohexagonal dodecahedron crystals were seen in SEM and TEM images. Exceptional air stability of CH3NH3PbI3 so forms are attributed to adsorption of CH2Cl2. Optical band gaps obtained from the diffused reflectance spectra (Kubelka Munk analysis), matched very well with the one estimated from Cyclic Voltammetry (CV). Valence band and conduction band edge positions estimated from the CV analysis are in good agreement with the one reported from UV photoelectron spectroscopy. Both the samples gave steady state fluorescence at ca. 750 nm with quantum yields in the range 15-35.5%. (C) 2016 Elsevier B.V. All rights reserved.