4-phenylenebis(methan-1-yl-1-ylidene)bis(4-pentylbenzenamine) (LCBAZ1) and N,N′-(1,4-phenylenebis(methan-1-yl-1-ylidene)bis(4-decylbenzenamine) (LCBAZ2) before and after protonation with the n-decyl sulfonic acid (DSA). The lengths of the outer spacers are four or nine methylene units connected with the imine group by phenyl ring in the para position. Liquid crystal properties of the undoped and doped azomethines