Abstract: 4-Alkoxybenzoic N-phenyl-N’-alkyl imidazolium esters were synthesized via copper(I) catalyzed Ullmann coupling reaction as key step.The mesophase behavior of these substances were studied by polarized optical microscopy(POM).These compounds can represent Smectic A mesophases when the length of the N-alkyl chains(CnH2n+1) was controlled between n=9—16.The mesophorbic behaviors of these compounds are analyzed as the result of both the microsegragation of the flexible alkyl chains from the rigid cores and the ion-ion interaction between the imidazoliums.