Black nanocarbon developed from bamboo (Gigantochloa scortechinii) was utilized as reinforcement for two thermoplastic polymers. The nanocomposites of polypropylene (PP) and polyamide-6 (PA-6) were synthesized by applying a coagulation scheme. Methanol was used as a coagulant for the nanocompos-ite preparation. Comparative analysis was accomplished with three percent filler mixing. Structural interpretation of the nanocomposite was carried out using Fourier-transform infrared (FTIR) spectroscopy. The investigation of the thermal and melting behavior of the nanocomposites was performed using thermogravi-metric analysis (TGA) and differential scanning calorimetry (DSC) techniques. The obtained results of the respective nanocomposite were interrelated to the neat PP and PA-6. A comparative investigation was done on the effective role of filler in each of the two polymers. The thermal analysis revealed that nanocomposites were stable at higher weight loss temperatures compared with their neat compos-ites. The two nanocomposites presented a different change in thermal properties with the same amount of the filler. DSC analysis disclosed the lowering in heat of melting of the coagulation processed products. © 2023 Nisa et al.