Using natural materials, i.e. halloysite nanoclay that is a biocompatible naturally occurring clay and Heracleum persicum extract that can serve as a green reducing agent, a novel magnetic catalyst, fe 3 o 4 / Hal-Mel-TEA(IL)-Pd, has been designed and fabricated. To prepare the catalyst, halloysite was first magnetized (magnetic particles with mean diameter of 13.06 ± 3.1 nm) and then surface functionalized with melamine, 1,4 dibromobutane and triethanolamine to provide ionic liquid on the halloysite surface (5 wt%). The latter was then used as a support to immobilize Pd nanoparticles that were reduced by Heracleum persicum extract. The characterization of the catalyst established that the loading of Pd in fe 3 o 4 /Hal-Mel-TEA(IL)-Pd was very low (0.93 wt%) and its specific surface area was 63 m 2 g −1 . Moreover, the catalyst showed magnetic property (Ms = 19.75 emu g −1 ) and could be magnetically separated from the reaction. The catalytic performance of the magnetic catalyst for reductive degradation of methyl orange and rhodamine B in the presence of NaBH 4 in aqueous media was investigated. The activation energy, enthalpy, and entropy for the reduction of methyl orange were estimated as 42.02 kJ mol −1 , 39.40 kJ mol −1 , and −139.06 J mol −1 K −1 , respectively. These values for rhodamine B were calculated as 39.97 kJ mol −1 , 34.33 kJ mol −1 , and −155.18 Jmol −1 K −1 , respectively. notably, fe 3 o 4 /Hal-Mel-TEA(IL)-Pd could be reused for eight reaction runs with negligible loss of the catalytic activity (~3%) and Pd leaching (0.01 wt% of the initial loading).Application of low-cost, biocompatible and available natural compounds for the catalytic purposes has attracted tremendous attention. In this regard, use of halloysite (Hal) that is a dioctahedral 1:1 clay of the kaolin group has received growing interest 1-3 . Apart from high thermal, chemical and mechanical stability, the cylindrical morphology and opposite chemical and electrical properties of inner and outer surfaces of Hal, make it distinguished from other clays and broaden its utility for many applications such as cleaning 4 , adsorbents 5,6 , energy storage, catalysis, flame retardancy 1 , sustainable release of drugs etc. Regarding catalysis, Hal not only can be utilized as a catalyst, but also can be applied as a support for the development of reusable catalysts. To date, various chemical, photochemical and electrochemical transformations such as coupling reactions 7,8 , hydrogenation 9,10 , oxidation have been promoted by using Hal-based catalysts [11][12][13][14][15] . Organic dyes such as methylene blue, rhodamine B (RhB) and methyl orange (MO) are toxic chemicals with potential health threat 16 . The release of these compounds in the industrial waste water has raised many concerns and motivated many studies for the efficient removal of these hazardous pollutants or their conversion into less toxic compounds 17,18 . In this context, several approaches, such as use of adsorbents, photodegradation, electrochemical degradations, membrane p...