Monolayers or submonolayers of zincphthalocyanine (ZnPc) deposited on highly oriented pyrolytic graphite (HOPG) substrates have been investigated by scanning tunneling microscopy (STM). Structures of ZnPc layers show characteristic low dimensional structures. When the ZnPc coverage is under 1 ML, twined stripestructures with three-fold symmetry were observed. This structure can be explained in terms of a commensurate superstructure of unit cell β form crystalline on the HOPG. When the ZnPc coverage is over 1 ML, one-dimensional structures like a wire were observed. The width and length of the wire are 6 nm and longer than 1 μm, respectively. These structures would also originate from the π-staking of ZnPc molecules.