The quest of a reliable method for fabricating ordered atomic-scale structures is a prequisite for future atomic-scale technology. The interest in such nanostructured materials, consisting of building blocks of a small number of atoms or molecules, arises from their promising new optic, catalytic, magnetic and electronic poperties. Here we present three examples concerning atomic and supramolecular self-assembly investigated by low-temperature scanning tunneling microscopy (STM). (i) The self-assembly of a two-dimensional array of individual Ce adatoms on a metal surface based on long-range interactions between adatoms mediated by surface state electrons [1,2]. (ii) The conservation of chirality in a hierarchical supramolecular self-assembly of pentagonal symmetry of the organic molecule rubrene on a reconstructed Au(111) surface . (iii) Using the highly localized current of electrons tunneling through a double barrier STM junction, we excite luminescence from a selected C60 molecule in the surface layer of fullerene nanocrystals self-assembled on an ultrathin NaCl film on Au(111). In the observed fluorescence and phosphorescence spectra, pure electronic as well as vibronically induced transitions of an individual C60 molecule are identified, leading to unambiguous chemical recognition on the single-molecular scale .  F. Silly, M. Pivetta, M. Ternes, F. Patthey, J. P. Pelz, and W.-D. Schneider, Phys. Rev. Lett. 92, 016101 (2004).  M. Ternes, C. Weber, M. Pivetta, F. Patthey, J. P. Pelz, T. Giamarchi, F. Mila, and W.-D. Schneider, Phys. Rev. Lett. 93, 146805 (2004).  M.-C. Blüm, E. Cavar, M. Pivetta, F. Patthey, W.-D. Schneider, Angew. Chem. Int. Ed. 44 , 5334 (2005).  E. Cavar, M.-C. Blüm, M. Pivetta, F. Patthey, M. Chergui, and W.-D. Schneider, Phys. Rev. Lett. 95, 196102 (2005).