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.