Langmuir-Blodgett (LB) monolayers of octaoctyloxy metallophthalocyanines (MOOPc, M = Cu, Zn) and copper tetra(tert-butyl) phthalocyanine were deposited on glass substrates. MOOPcs showed gradual increase in their surface pressure-area isotherms reflecting their flexible substituents. In spite of the similar molecular structure, Cu and ZnOOPc indicated different isotherms at lower pressure, manifested by the surface morphology. At high surface pressure, ZnOOPc monolayer became denser than CuOOPc monolayer, as was estimated by the optical absorption. These results represents that the central metals have a crucial effect on structures of LB monolayers. [DOI: 10.1380/ejssnt.2015.155]