After 17,19-dotetracontadiyne (DTDY) mono-molecular layer was formed onto highly ordered pyrolytic graphite by vacuum deposition, copper-phthalocyanine (CuPc) was successively deposited on the DTDY layer. Depending on the coverage of CuPc molecules on the DTDY layer, the CuPc changed in their aggregation states. When a small amount of CuPc molecule was deposited, one-dimensional alignment of CuPc molecules was formed along a line of the DTDY columnar axis. With increasing the amount of deposited CuPc, two-dimensional domains were formed and exhibit the point-on-line coincidence with respect to the underlying DTDY layer. The one-dimensional alignment of CuPc was observed also along a column axis of the n-tetratriacontane mono-molecular layer prepared in the same way. (C) 2004 Elsevier B.V. All rights reserved.