Phase pure nanosized BiFeO3 (BFO) powder was synthesized by sol–gel method based on the propylene glycol-gel reaction. The formation mechanism, crystal structure, magnetic and optical properties were investigated by thermogravimetry, differential thermal analysis, infrared spectroscopy, X–ray diffractometry, Rietveld analysis, Raman spectroscopy, transmission electron microscopy, SQUID magnetometry and ultraviolet–visible spectroscopy. X–ray diffraction and Raman studies revealed the formation of pure and well-crystallized BFO nanocrystallites at a low temperature of 400°C. The BFO nanoparticles showed weak ferromagnetic property at room temperature due to size-confinement effects. The UV–visible spectra showed strong band-gap absorption at ~590 nm (2.1 eV) for BFO nanoparticles suggesting their potential application as visible-light-response photocatalyst.