We present a systematic study of metal-organic honeycomb lattices assembled from simple ditopic molecular bricks and Co atoms on Ag(111). This approach enables us to fabricate size- and shape-controlled open nanomeshes with pore dimensions up to 5.7 nm. The networks are thermally robust while extending over mu m(2) large areas as single domains. They are shape resistant in the presence of further deposited materials and represent templates to organize guest species and realize molecular rotary systems.