pattern. Thus, dimeric (1c, 1d, and 1u) and tetrameric (1f) aggregates with strong NH···OC hydrogen bonding, as well as polymeric chain structures (1x and 1z) were observed in the solid state. Furthermore, a dimer 1k involving only the amidine subunits, rather than the carbonyl function, was found. Monolayers of molecules 1u and 1ab physisorbed at the liquid/HOPG (high orientated pyrolytic graphite)