A design strategy for fabricating a surface-supported chiral metal-organic system comprising a regular arrangement of mononuclear iron centers and nanocavities is presented. By sequential deposition of 1,2,4-benzenetricarboxylic acid (tmla) molecules and iron atoms on a Cu(100) surface under ultrahigh vacuum conditions, chiral square-planar Fe(tmla)4 metal-organic complexes are generated, which order in extended homochiral arrays. Structure formation and envisioned functionality of such metal-organic architectures are discussed.