Abstract A new magnetic-responsive deep-eutectic (MDE) was detected by screening the components at different mole ratios in the solid-liquid equilibrated mixtures of CoCl2·6H2O and choline chloride (ChCl) followed by vacuum evaporation. Among these complexes, the bluish complex 2ChCl·2Ch+:CoCl42− (Co4ChDES), given at 1:4 mol ratio of CoCl2:ChCl showed a very deep decrease in mp as well as paramagnetic properties. All complexes were compared by mp, UV–vis, and FT-IR, while the Co4ChDES was finely analyzed by energy-dispersive X-ray spectroscopy (EDX), vibrating sample magnetometery (VSM), and EDS mapping. The positive magnetic response, surface elemental analysis, and characteristic UV–vis absorption wavelengths for Co4ChDES confirmed the presence of magnetic tetrahedral counter ion CoCl42− in the structure of this DES. The anionic complex CoCl42− which provides magnetically recovering of Co4ChDES in cooperation with the four choline groups are hydrogen bond-acceptor and hydrogen bond-donor components of this DES. The 0.75 mol% and 1.5 mol% of Co4ChDES represented high catalytic performance in the water-based multi-component reactions (MCRs) for the synthesis of substituted tetrahydropyrazolopyridines (THDPPs) and pyrroles under very mild conditions. High efficiency, simple recovery, and reusability are advantages of this non-corrosive liquefy catalyst which makes it a better alternative than that homogenous liquid acid catalysts.