A new nickel(II)-dicyanamide compound, [Ni(dca)2(en)]n (1) (dca=dicyanamide anion, -); en=ethylene diamine), has been synthesized and its structure has been determined by single crystal X-ray diffraction analysis. The crystal is monoclinic, space group P21/n with unit cell dimensions: a=0.694 3(1) nm, b=1.041 5(2) nm, c=1.413 2(2) nm, and β=90.381°, Z=4, V=1.011 0(3) nm3. In this compound, the adjacent nickel atoms are connected by dca all inμ1,5-bridging mode to form ladder-like units, which are linked with double dca bridges to generate a regular infinite stair-like structure. Temperature-dependent magnetic susceptibility was also characterized for this compound. CCDC: 208276.