More research interest is developing rapidly on two dimensional (2D) materials owing to their excellent electro-optic properties to develop next generation of electronics and highly functional devices. Among well-known and widely used 2D materials, boron nitride (BN) is an electrical insulator with a band gap of 5.5 eV, and attests high chemical stability, outstanding mechanical properties, and high thermal conductivity. Accordingly, BN is considered as a promising candidate to improve the heat dissipation material performance. In this study, the cooling rate of composite materials of poly methyl methacrylate (PMMA), hexagonal boron nitride (h-BN) and gold nanoparticles was investigated using femtosecond transient absorption spectroscopy. The main objective of this study is to prepare the flexible BN-PMMA films could have a significant impact on heat dissipation to enhance the performance of electronics devices. BN nanostructures were prepared by nanosecond laser ablation in acetone. The laser ablation was carried out at room temperature with laser ablation time of 120 min. The SEM images of bulk BN and laser ablated BN were obtained for structural and surface morphological characterization. Gold colloidal solution was prepared using gold nano-particles with chloroauric acid and distilled water. For the preparation of composite film, PMMA was dissolved in acetone solvent and then mixed with BN and gold colloid solution. The prepared composite films were examined for cooling rate of photoexcited gold nanoparticles using femtosecond transient absorption spectroscopy. It is found that the lifetime is shorter for composite films with Au and high BN content.