The report states that well-dispersed CoFe2O4 nanoparticles (NPs) with controllable morphology were prepared using an economical and facile one-pot thermal decomposition approach. Cobalt (II) acetylacetonate and Iron (III) acetylacetonate were employed as precursors instead of expensive and toxic pentacarbonyl. The transmission electron microscopy and powder X-ray diffraction investigation show that CoFe2O4 NPs possess cubic morphology, homogeneous size distribution and pure phase structure. Optical band gap was tuned from 1.147 to 0.92 eV and saturation magnetization (M (s)) increased from 53.91 to 84.01 emu/g for the as-prepared and annealed (700 A degrees C) NPs. The coercivity (H (c)) enhanced from 1137 to 2109 Oe at room temperature, which is the highest value reported to date for CoFe2O4 NPs synthesized by thermal decomposition. All CoFe2O4 (as-prepared and annealed) NPs showed excellent ferromagnetism behaviour at room temperature. Raman studies of CoFe2O4 NPs confirm the redistribution of Co2+ from octahedral to tetrahedral site. The work demonstrates the great potential of CoFe2O4 NPs as a promising alternative for data storage device applications as well as for opto-magnetic devices.