doi:10.1002/adma.202511061engPalacios, ElíasAguilà, DavidGracia, DavidManiaki, DiamatoulaBarrios, Leoní A.Chiesa, AlessandroMartínez, Jesús I.Novikov, ValentinRoubeau, OlivierCarretta, StefanoEvangelisti, MarcoAromí, GuillemLuis, FernandoSelf‐Cooling Molecular Spin QuditsART-2025-146307The need of operating molecular spin qubits at very low temperatures constitutes a technological limitation. This challenge is addressed by integrating, in the same material and at the molecular scale, quantum processing and magnetic refrigeration capabilities. The molecular unit is a [GdEr] heterolanthanide coordination complex, where Er(III) encodes a qubit while Gd(III) provides a large magnetocaloric effect. The properties of each component are separately studied in isostructural [LaEr] and [GdLu] complexes, where each functional ion lies next to a diamagnetic metal. All complexes are characterized by magnetic, heat capacity, and EPR measurements. The results show that the presence of both ions in the same molecule has a synergic effect on both functionalities. Thus, the coupling between Er(III) and Gd(III) spins lifts any level degeneracies even close to zero magnetic field, leading to a d = 16 set of spin states that, as revealed by pulse EPR measurements, can be coherently manipulated. In turn, Er(III) enhances the magnetocaloric effect compared to [GdLu], extending it to lower temperatures. This is corroborated by direct magnetocaloric measurements, which show the ability of this material to cool itself, and a device, down to temperatures as low as 0.4 K.2025http://zaguan.unizar.es/record/16404410.1002/adma.202511061http://zaguan.unizar.es/record/164044oai:zaguan.unizar.es:164044info:eu-repo/grantAgreement/ES/AEI/AEI PID2022-140923NB-C21info:eu-repo/grantAgreement/ES/DGA/E09-23R-QMADinfo:eu-repo/grantAgreement/ES/DGA/E11-23R-M4info:eu-repo/grantAgreement/ES/DGA/E31-23R-PLATONinfo:eu-repo/grantAgreement/ES/MICINN/CEX2023-001286-Sinfo:eu-repo/grantAgreement/ES/MICINN/PDC2022-133184-I00info:eu-repo/grantAgreement/ES/MICINN/PID2020-1183294RB-I00info:eu-repo/grantAgreement/ES/MICINN/PID2021-124734OB-C21info:eu-repo/grantAgreement/ES/MICINN/PID2022-137764OB-I00info:eu-repo/grantAgreement/EUR/MICINN/TED2021-129214B-I00info:eu-repo/grantAgreement/EUR/MICINN/TED2021-131447B-C21Advanced materials (2025), e11061 [7 pp.]by-nc-ndhttps://creativecommons.org/licenses/by-nc-nd/4.0/deed.esinfo:eu-repo/semantics/openAccess