A stable D-III-dispersed compound with single-molecule magnet behavior, Dy0.06Y0.94(OH)CO3, was isolated by a general strategy targeted at the doping, of paramagnetic Dy3+ into a diamagnetic 3D inorganic network of Y(OH)CO3. The single-ion origin of slow magnetic relaxation was gradually released as variations of the dysprosium/yttrium ratio and finally gave a relatively large spin-reversal barrier around 200 K and high hysteresis temperature of 8 K. This study opens up new opportunities to investigate the slow magnetic relaxation and magneto structural correlation by choosing a suitable inorganic architecture with strong axial anisotropy.