Ultrasound-assisted synthesis of novel pyrazoles using Ni-Mg-Fe LDH as a catalyst in cyclopentyl methyl ether (CPME) is introduced. Different LDHs were tested as a catalyst for the synthesis of pyrazoles via a 1,3-dipolar cycloaddition reaction. Among them, Ni-Mg-Fe LDH was the superior catalyst for this reaction. This protocol offered high yields, a short reaction time, and a green solvent, and with the reuse of this catalyst six times with the same activity, it could be regarded as an ecofriendly, greener process. The NiMgFe LDH catalyst with the smallest particle size (29 nm) and largest surface area showed its superior efficacy for the 1,3 dipolar cycloaddition rection and can be successfully used in up to six catalytic cycles with little loss of catalytic activity. A plausible mechanism for this reaction over the Ni-Mg-Fe LDH is proposed.