L1₀-ordered FePt nanoparticles (NPs) with ultra-high coercivity were directly prepared from a new metallopolyyne using a one-step pyrolysis method. The chemical ordering, morphology and magnetic properties of the as-synthesized FePt NPs have been studied. Magnetic measurements show the coercivity of these FePt NPs is as high as 3.6 T. Comparison of NPs synthesized under the Ar and Ar/H₂ atmospheres shows that the presence of H₂ in the annealing environment influences the nucleation and promotes the growth of L1₀-FePt NPs. Application of this metallopolymer for bit-patterned media was also demonstrated using nanoimprint lithography.