Semimagnetic Bi2-xMnxS3 nanocrystals (NCs) with a mean size of approximately 4.0 nm were successfully synthesized by fusion in a host glass and investigated by several experimental techniques. Transmission electron microscopy and atomic force microscopy/magnetic force microscopy images confirmed the growth of the Bi2-xMn xS3 NC samples, showing uniform distribution of the total magnetic moment in the nanocrystals. X-ray diffraction measurements revealed that the as-produced nanocrystals are single-phase, nanosized, and crystallized in the orthorrombic structure and that Mn2+-ions had replaced Bi 3+-ions. Electron paramagnetic resonance (EPR) spectra of the doped samples showed six hyperfine lines associated with the S = 5/2 spin half-filled d-state and characteristic of Mn2+ ions. EPR spectra simulated compared fairly well with experimental results and indicated the incorporation of Mn2+ ions in the core and surface in Bi2-xMn xS3 NCs. © 2014 American Chemical Society.