 Researchers are exploring natural filler options for polymer composites in structural and automotive applications, including Sirisha Bark as an alternate filler with enhanced properties such as low-cost, eco-friendliness, and non-toxicity. The Sirisha Bark filler has a density of 0.713 gcc, with cellulose, hemicellulose, lignin, moisture, and ash content of 68.23%, 13.26%, 13.25%, 12.66%, and 1.82% respectively, a crystallinity index of 65.71%. Thermal stability up to 429 degrees Celsius with an activation energy of 54.5 kW per mole, and trace elements like Ca and R at 1.3% and 2.54%. This article was authored by Tanmayi Kuncha and Sandhya Rani Bisphos.