The copper complexes of tetra-4-[(n-alkoxy)carbonyl] phthalocyanines 1 and tetra-[(4,4',4'',4"'-carboxyl),(5,5',5",5'''-alkoxycarbonyl)] phthalocyanines 2 have been synthesized and the influence of the variation of the number, polarity or the length of the lateral substituents on their thermotropic and lyotropic mesomorphism has been studied. For the first time it has been shown that the homologous of both series can display lyotropic and thermotropic mesophases, i.e. amphotropy. The structure - properties relationship of these two mesomorphic series has been discussed as a consequence of the micro-segregation in the thermotropic as well as in the lyotropic state.