In this research, for the first time, caffeine and citrulline are used as fuels in synthesizing spinel ferrite CoFe2O4 by gel combustion. The influence of the oxidizer to fuel molar ratio ( [[EQUATION]] ) were studied in the synthesis of cobalt ferrite. X-Ray Diffraction (XRD) showed that the spinel phase was obtained in all the combustions, but the caffeine fuel allows obtaining it with high purity, while in the other combustions appears the presence of CoO as a secondary phase due to changes in the reaction. Furthermore, the crystallite size increased with the increased amount of fuel, and it was found to be in the range of 32 nm – 40 nm. In addition, the adiabatic flame temperatures were estimated, in the synthesis with [[EQUATION]] = 0.7, the flame temperatures were 1974 K and 1711 K, respectively, which could be sufficient to obtain the phase in one stage. The ignition temperature obtained by DSC/TG thermal analysis for caffeine and citrulline samples with φ = 1.0 were 297 and 191 °C, respectively, which are in the range of traditional fuels. The morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) which revealed that the particles are agglomerated as a result of high reaction temperatures. The magnetic properties obtained by the vibrating sample magnetometer (VSM) for sample with caffeine and ratio φ = 0.7 were saturation magnetization Ms = 95.16 emu g-1, coercivity field Hc = 710.76 Oe and remanent magnetization Mr = 44.86 emu g-1. It should be pointed out that the high saturation magnetization value displayed exceeds the ones reported with traditional fuels. The obtained results allow us to infer that these fuels could be used as alternatives in synthesizing inorganic oxides by combustion in one step.