 First principles calculations investigate the crystal structures, elastic and anisotropic properties of CH3NH3BX3B equals SN, PB, X equals BR, I, compounds as solar cell absorber layers, revealing that BX bonds and organic cations are crucial to their functionalities. The bulk, shear, Young's modulus ranges from 12 to 30 GPA, 3 to 12 GPA, and 15 to 37 GPA respectively, with negligible effect of interaction among organic and inorganic ions for elastic properties. The B slash G and Poisson's ratio show good ductal ability for extensive deformation as a flexible slash stretchable layer on the polymer substrate due to low shear modulus. Anisotropic indices reveal strong anisotropy derived from elastic constants, chemical bonds, and symmetry in ABX3 perovskite. This article was authored by Jing Feng. We are article.tv, links in the description below.