In this study, MnCoFe2O4@ ovalbumin nanoparticles were synthesized using MnCoFe2O4 MNPs and egg white nano-ovalbumin. The surface of MnCoFe2O4 MNPs was activated with trisodium citrate anhydrou to improve the fabrication ofn nano-ovalbumin on MCF MNPs. The structure of these nanoparticles was properly characterized by Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscope, X-ray powder diffraction, Energy-dispersive X-ray spectroscopy, Transmission electron microscopy, Thermogravimetric, and Vibrating sample magnetometer. The catalytic activity of the MnCoFe2O4@ovalbumin nanoparticles was evaluated for the synthesis of pyrimido[4,5-d]pyrimidine derivatives via multicomponent reaction of aldehyde, barbituric acid, urea, or thiourea under solvent-free condition. The desired products were prepared using an environmentally friendly method. Short reaction time, high efficiency, and easy work-up are some advantages of this procedure. This heterogeneous nanocatalyst can be easily recovered by a magnetic field and used at least six times without considerable loss of its activity. Also, MCF@OVL MNPs exhibited a CO2 adsorption capacity about 9.35 mmol/g at 25 °C.