Square-planar S = <sup>1sup>/<sub>2sub> Ag<sup>IIsup> ions in polymeric Ag(nic)<sub>2sub> are linked by bridging nic monoanions to yield 2D corrugated sheets. Long-range magnetic order occurs below T<sub>Nsub> = 11.8(2) K due to interlayer couplings that are estimated to be about 30 times weaker than the intralayer exchange interaction.