The liquid crystalline properties of a series of main chain liquid crystalline polymers and four series compounds consisting of aromatic type Schiff base mesogenic units and polymethylene flexible spacers were studied. The thermal and liquid crystalline properties were investigated by differential scanning calorimetry and on the hot stage of a polarizing microscope. The nature of the liquid crystalline phase of the polymers and compounds depended greatly on the length of the central polymethylene spacer and on the terminal alkoxy groups. Polymers I and Series III exhibited an even-odd effect in melting and isotropization temperatures but Series II and Series IV exhibited an even-odd effect in isotropization temperatures. They formed nematic and smectic mesophases in melts as judged by their optical textures observed through a polarizing microscope.