A novel nanomagnetic basic catalyst of caesium carbonate supported on hydroxyapatite-coated Ni0.5Zn0.5Fe2O4 magnetic nano- particles (Ni0.5Zn0.5Fe2O4@HAP-Cs2CO3) 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 deriv- atives. Also, Ni0.5Zn0.5Fe2O4@HAP-Cs2CO3 could be reused at least five times without significant loss of activity and could be recov- ered easily by applying an external magnet. Thus, the developed nanomagnetic catalyst is potentially useful for the green and economic production of organic compounds.