Photodynamic therapy (PDT) and photothermal therapy (PTT) using nanoparticles have gained significant attention for its therapeutic effect for cancer treatment. In the present study, we fabricated polypyrrole nanoparticles by employing bovine serum albumin-phycocyanin complex and the formulated particles were stable in various physiological solutions like water, phosphate buffered saline and culture media. The formulated nanoparticles did not cause any noticeable toxicity to MDA-MB-231 and HEK-293 cells. The obtained nanoparticles effectively killed MDA-MB-231 cells in a dual way upon laser illumination, one is through phycocyanin propagated reactive oxygen species (PDT) upon laser illumination and in another way it eradicated the treated cells by converting optical energy into heat energy (PTT). Additionally, the nanoparticles generated good amplitude of ultrasound signals under photoacoustic imaging (PAT) system that facilitates imaging of treated cells. In conclusion, the fabricated particles could be used as a multimodal therapeutic agent for treatment of cancer in the biomedical field.