In the current scenario, microbial infections are major concern and they multiply so rapidly throughout the world; also, they cause serious bio illness and can even results in death among humans. Complexes framed by crystalline metal ions have been used as medications, because of a wide range of organic activities against harmful microorganisms. In the present study, greenish blue potassium tetrachlorocuprate (II) dihydrate K2CuCl4.2H2O crystalline precipitates were prepared by solvent evaporation method at ambient temperature. This complex was found in nature as a rare mineral Mitscherlichite. For finding the crystalline parameters of the sample, a Single-crystal XRD analysis was used and the data confirms. K2CuCl4.2H2O crystallizes into a tetragonal structure. The formation of bonds and the presence of functional groups in the complex were determined from Surface morphology studies, the very clear morphology of the complex has smoothing surface, defect-free, small microstructures and stacklike shapes of a well-defined crystalline pattern. Also, addition, optical analysis supports that its possibility in antimicrobial applications. The sample shows comparatively good results in positive control of antibacterial and antifungal activities, namely Gentamicin, Chloramphenicol and Clotrimazole. IC50 and optical density (OD) values were used to determine the cytotoxicity and cell viability, respectively. In vitro cytotoxicity of MTT assay shows in graphical abstract.