A novel nanomagnetic basic catalyst of caesium carbonate supported on hydroxyapatite-coated Ni 0.5 Zn 0.5 Fe 2 O 4 magnetic nanoparticles (Ni 0.5 Zn 0.5 Fe 2 O 4 @HAP-Cs 2 CO 3 ) was prepared. This new catalyst was fully characterized using Fourier transform infrared spectroscopy, transmission and scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry techniques, and then the catalytic activity of this catalyst was investigated in the synthesis of 1H-pyrazolo[1,2-b]phthalazine-5,10-dione derivatives. Also, Ni 0.5 Zn 0.5 Fe 2 O 4 @HAP-Cs 2 CO 3 could be reused at least five times without significant loss of activity and could be recovered easily by applying an external magnet. Thus, the developed nanomagnetic catalyst is potentially useful for the green and economic production of organic compounds.

In the present study CuII anchored onto the magnetic talc (γ‐Fe2O3/ talc /CuII NPs) was successfully synthesized and characterized by FT‐IR, XRD, TEM, FE‐SEM, EDX, VSM, and ICP‐OES techniques. Structural characterizations reveal that the γ‐Fe2O3/talc/CuII NPs are superparamagnetic in nature, structured as a composite with average diameter of about 19–31 nm. The prepared nanostructured catalyst efficiently catalyzed the preparation of 1H‐pyrazolo[1,2‐b] phthalazine‐5,10‐diones at the gram scale without the use of the toxic organic solvents. The magnetically separable and environmentally friendly nanostructured catalyst remains quite stable during reaction conditions and reused for at least five recycle runs.