In this study, cobalt chromite (CoCr2O4) nano pigments were synthesized in a microwave oven at 180 A degrees C for 2 h by using corresponding metal acetates in diethylene glycol media. The resulting powders (as-synthesized and calcined) were successfully characterized by X-ray diffraction, thermogravimetry-differential scanning calorimetry, fourier transform infrared, field emission scanning electron microscopy and dynamic light scattering method. Results show that the as-prepared powders consist of amorphous compound with 30 nm average particle size. Upon calcination of this product, CoCr2O4 spinel phase starts forming at 400 A degrees C and stable spinel phase formation was completed at 700 A degrees C. The pigment calcined at 700 A degrees C for 3 h showed blue-green hue by ultraviolet-visible spectra. In addition, the particle size distribution remained nano size even after calcination.