A new flexible Salen-type dysprosium coordination polymer, [Dy 2 (H 2 L) 2 (NO 3 ) 4 (CH 3 O) 2 ] n (1) (H 2 L=N,N′-bis(salicylidene)-1,4-butane-diamine), has been synthesized by a solvothermal method. The single-crystal X-ray diffraction studies reveal that complex 1 features a two dimension (2D) network structure with rare dinuclear units. Each Dy(III) ion is eight-coordinated where the μ 2 -(OCH 3 ) 2 bridged Dy 2 O 2 cores are linked by four Salen-type ligands in bidentate fashion. Magnetic studies reveal that complex 1 presents antiferromagnetic interactions between Dy(III) centers and exhibits the frequency dependent peaks, a behavior characteristic of a single-molecule magnet.