Iron oxide nanoparticles (IONPs) have been the subject of significant interest owing to their intriguing properties and wide array of applications. The present communication reports three disparate energy efficient methods for the synthesis of Fe3O4 nanoparticles, namely chemical co-precipitation, sol–gel and hydrothermal methods, followed by annealing at a temperature of 400 °C for 2 h to optimize the parameters under study. X-ray diffraction (XRD) was employed for structural analysis, along with scanning electron microscopy (SEM) for morphological analysis. The structural properties of the material were found to be influenced by the synthesis technique used. The dielectric parameters, including the dielectric constant (ℇ′) and dielectric loss tangent (tan δ) of the samples synthesized through all three methods were examined over a frequency span of 20 Hz–10 MHz and temperatures ranging from 40 to 300 °C in vacuum. Tangent loss as well as the dielectric constant were determined to be higher in the case of nanoparticles synthesized using chemical co-precipitation. Temperature increments also led to significant enhancement of dielectric parameters owing to elevated conductivity and polarization. Further, a vibrating sample magnetometer (VSM) was utilized for analysis of the magnetic behavior. The highest saturation magnetization value of 35.30 emu/gm ascribed to the chemical co-precipitation synthesis method.