We have studied four binary systems comprising of four mesogenic components viz., 4-nitrophenyl-4(!)-n-alkoxy benzoates (where n-alkoxy group is n-butoxy, n-hexyloxy, n-octyloxy and n-decyloxy) and a non-mesogenic component namely., 4-n-decyloxy-4(!)-l-(s)-methyl propoxy azobenzene. A wide variety of mixed mesomorphic properties are observed in these mixtures. The properties of these systems are discussed on the basis of phase diagrams.