Surface-confined molecular networks can serve as templates to steer the adsorption and organization of secondary ligands, metal atoms, and clusters. Here, the incorporation of Ni atoms and clusters into open two-dimensional robust metal-organic templates self-assembled from butadiyne dibenzoic acid molecules and Fe atoms on Au(111) and Ag(100) surfaces is investigated by scanning tunneling microscopy. The metal substrate plays a crucial role in the interaction of Ni atoms with the metal-organic host networks. On Ag(100) the metal-organic template steers the growth of Ni clusters underneath the network pattern near the central butadiyne moiety. In contrast, on Au(111) Ni interacts preferentially with the benzene rings forming sue limited clusters inside the network cavities. Thereby, on both surfaces Ni clusters consisting of a few atoms with both high areal density and thermal stability up to 450 K are realized The Ni-functionalized networks enable the coordination of additional molecules into the open structures demonstrating the utilization of selective interactions for the assembly of multicomponent,. architectures at different organizational stages.