This paper describes the synthesis and the characherisation of the phase behaviour of a homologous series based on the macrocycle 1,7-diaza-4,10,13-tri-oxa-cyclopentadecane. The mesogenic units attached to the two aza-groups consist of three aromatic rings and the length of the terminal chain is varied between six and sixteen methylene groups. Three different types of tilted smectic phases were observed which are believed to differ in their layer packing in that one may have aligned tilt (normal smectic C) and the other two may have alternating tilt.