New pyridylsalicylaldimine;based ligands with ex, tended conjugation,have been synthesized. The reaction of these ligands with k(2)PtCl(4) yielded triangular Pt-3 macrocycles rather than the anticipated Pt-4 macrocycles: The rnacrocycles have been. analyzed in solution by variable-temperature and,Variable-concentration H-1 NMR, NOESY, and DOSY spectroscopy studies. These investigations show that the macrocydes;aggregate at room temperature in solution by an entropy-driven process. In the solid,state,. rriatrixassisted laser desorption/ionization time-of-flight mass spectrometry and, frangnision electron microscopy studies Show that the acrocycles aggregate into nanotubular structures. Triangular;platinum-containing, macrocydes with the expanded pyiidylsalicy-laidiMine ligands are promising for constructing nanotubes and discotic liquid crystals.