A series of compounds of the formula [MnCl(L-n)(2)] (L= N-alkyl[4-(4-decyloxybenzoyloxy)]salicylaldiminato) have been synthesized and their mesomorphic properties studied. These Mn(III) complexes display monotropic nematic phases when the number of carbon atoms of the N-alkyl moiety has from 3 to 9 carbon atoms, Compounds ranging from 5 to 9 carbon atoms also display monotropic smectic C phases. When the N-alkyl part is longer (10 to 16 carbon atoms) only enantiotropic smectic C phases appear. Two complexes were studied by X-ray diffraction showing diffraction patterns that account for the peculiar molecular shape of these molecules.