Nano‐scaled coordination complexes (CC) exhibiting the structures [Ag (INH)2].OH.H2O (CC1), [Ni(4,4′‐bpy)(H2O)4](4‐aba)2.4H2O (CC2), (INH = isonicotinic acid, 4,4′‐bpy = 4,4′‐bipyridine, 4‐aba = aminobenzoate) were prepared via self‐assembly and sono‐chemical methods at ambient conditions. The structures were fully studied by single‐crystal XRD and analytical investigations. Water molecules and the hydroxyl ions act as guests connecting the discrete molecules in complex 1, whereas in 2 the coordinate water molecules form the 1D chains of [Ni(4,4′‐bpy)(H2O)4] which are H‐bonded to the guest H2O molecules and aminobenzoate anions. The structures of CC 1 and 2 are stabilized into 3D‐supramolecular topology through H bonds and π–π stacking interactions. The nanosized tested compounds 1\ and 2\ are designed to investigate their action on viability and proliferation of five human cancer cell lines. In addition, ABTS assay and rate erythrocyte hemolysis were used to test the antioxidant activity of the nanosized 1\ and 2\. Also, the coordination complexes 1\ and 2\ exhibit good antimicrobial activity keeping them as promising drug candidates for the treatment of bacterial and fungal infections.