Coumarinic compounds are a class of lactones, structurally constructed with fusion of a benzene ring and ?-pyrone ring. Previous research studies have demonstrated that coumarin and its derivatives exhibit many pharmacological properties such as antitumor, antibacterial, antifungal, anticoagulant, antioxidant, anti- inflammatory and many others. In this study we had dealt with its antimicrobial activity followed by pH analysis. The aims of this study are to prepare and identify the crude coumarin extracted from cassia cinnamon and to study its antimicrobial activity. The antimicrobial activity of extracted crude coumarin from cinnamon sample was tested for antimicrobial pattern against gram positive, gram negative bacteria and fungi. The study of Minimum inhibitory concentration was performed by disc diffusion method. The highest activity in terms of zone of inhibition (22.32mm) was observed against gram negative bacteria E.coli(shown in fig.6).Other gram positive bacteria staphylococcus aureus was also found susceptible to ethanolic extract and inhibition zone was noted as a 12.61mm (shown in fig.7). C. albicans fungi was also found susceptible to ethanolic extract and inhibitory zone was recorded Ambiguously in a wide range between 5-19 mm. However, there was no zone of inhibition found for aqueous extract form. In comparison with broad spectrum antimicrobial activity, maximum antibacterial activity was shown by E.coli followed S. aureus. The pH analysis was performed & it was found to be non-reactive with different acid & bases (Strong & Weak), So it cannot be used for titrimetric analysis although it has pigment but it can be effectively used as one of the active ingredient on skin without concerning about the change in pH of formulation.