In this work, anhydrous cobalt salts of cobalt chloride and cobalt nitrate (CoCl2 and Co(NO3)2) were stabilized on the silica gel surface. Characterization of these nanoparticles was investigated by the FT-IR (Fourier Transform Infrared Spectroscopy), FE-SEM (Field Emission Scanning Electron Microscope), EDS (Energy ‐Dispersive X‐Ray Spectroscopy), XRD (X-ray Diffraction), and ICO-OES (Inductively Coupled Plasma Optical Emission Spectroscopy). Furthermore, the efficiency of these nanoparticles was investigated for one-pot synthesis of pyranopyrazole and spiropyranopyrazole derivatives via a four-component reaction of hydrazines, ethyl acetoacetate, aldehyde or isatine derivatives, and malononitrile or ethyl cyanoacetate under green media. The obtained data from EDX and ICO-OES analyses confirm the amount of cobalt metal in SiO2@CoCl2 is more than that in SiO2@Co(NO3)2. The availability and reusability of SiO2@CoCl2 catalyst without its significant reduction in catalytic efficiency during six runs, suitable reaction times, easy workup procedure and good efficiency are some advantages of this green procedure.
