<p>The increasing demand for sustainable carbon management and environmental remediation has elevated the importance of advanced biochar as a critical material for addressing global challenges in carbon sequestration, soil restoration, and pollutant mitigation. This perspective presents a focused review on microwave co-pyrolysis involving lignocellulosic biomass and algal feedstocks, emphasizing emerging synergies in biochar quality and process efficiency. The integration of post-treatment techniques such as ball milling and ultrasonic treatment further supports the conversion into nano-biochar (a nanostructured material) with improved adsorption capacity, catalytic efficiency, and adaptability across applications in water treatment, pollutant remediation, and carbon capture. This perspective explores the technological advantages of microwave co-pyrolysis, including its rapid and uniform heating mechanisms and synergistic feedstock interactions, which overcome the limitations of conventional methods. It also shows potential in addressing challenges to large-scale adoption, such as feedstock variability, production costs, and process scalability, while proposing pathways for advancing this technology toward a sustainable biochar economy. By linking material science innovation to broader environmental and societal goals, this perspective emphasizes the transformative potential of nano-biochar to support climate mitigation, promote sustainable agriculture, and contribute to global carbon neutrality efforts.</p> Graphical abstract <p></p>