A potent semiorganic third order acentric crystal Poly[μ-chlorido-heptachlorido-μ3-L-proline-μ2-L-proline-tetramercury(II)] (LPDMCl) with the chemical formula [Hg4Cl8(C5H9NO2)2]n was crystallized by slow evaporation in water and thereby its second and third order optical nonlinearities are explored using the technique of SHG powder test of Kurtz-Perry and Z-scan single beam respectively. The grown crystalline material was analyzed by single crystal XRD, which discloses the acentric space group P1 of the material with the crystal system of triclinic. From XRD analysis, the obtained peaks were indexed correlated to the orientations of (hkl) plane thus displaying the crystalline purity and perfection. FTIR spectrum detailed the diverse vibrational modes, which signifies the functional groups in LPDMCl. Surface topology of the crystallized salts was accomplished by the examination of SEM. Mechanical, dielectric, linear and nonlinear optical investigation were performed to affirm LPDMCl as an aspiring candidate in establishing proficient nonlinear optical and optical power limiting device for practical applications. © 2020 Elsevier B.V.