[en] 2D conductive metal–organic frameworks (2D c‐MOFs) feature promising applications as chemiresistive sensors, electrode materials, electrocatalysts, and electronic devices. However, exploration of the spin‐polarized transport in this emerging materials and development of the relevant spintronics have not yet been implemented. In this work, layer‐by‐layer assembly was applied to fabricate highly crystalline and oriented thin films of a 2D c‐MOF, Cu${}_3$(HHTP)${}_2$, (HHTP: 2,3,6,7,10,11‐hexahydroxytriphenylene), with tunable thicknesses on the La${}_{0.67}$Sr${}_{0.33}$MnO${}_3$ (LSMO) ferromagnetic electrode. The magnetoresistance (MR) of the LSMO/Cu${}_3$(HHTP)${}_2$/Co organic spin valves (OSVs) reaches up to 25 % at 10 K. The MR can be retained with good film thickness adaptability varied from 30 to 100 nm and also at high temperatures (up to 200 K). This work demonstrates the first potential applications of 2D c‐MOFs in spintronics. (© 2020 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)