Highly crystalline CoFe
2
O
4
nanoparticles (
d
~ 5.6 nm) were synthesized by thermal decomposition of (i) single molecular precursor CoFe
2
(O
t
Bu)
8
and (ii) stoichiometric mixture of individual metal precursors. The precursors were thermolyzed in a high-boiling solvent (Docosane, bp. 369 °C) to produce uniformly dispersed cobalt ferrite nanoparticles in the case of molecular pre-cursor, whereas bimodal distribution of nanoparticles was obtained in the multi-source synthesis. TG/DSC and HR-TEM reveraled single- and multi-step decomposition profiles and differential nucleation steps in the two cases, which influence size dispersion and phase purity.