Self-assembly between simple unsymmetrical ligands, such as 1-(3pyridyl)-2-(4-pyridyl)ethene (L 1) and 1-methyl-1′ -(3-pyridyl)-2-(4-pyrimidyl)ethene (L 2), and Co(NCS) 2 affords the unprecedented two-dimensional grid coordination polymers [Co(L 1) 2(NCS) 2] ∞ (1) and [Co(L 2) 2(NCS) 2] ∞ (2), respectively, with novel topological features which cannot be achieved using symmetrically bridging ligands.