Statistical copolymers with mesogenic and non-mesogenic comonomer units were synthesized by partial hydroboration of the 1,2-units of polybutadiene and subsequent conversion of the alcohol groups to mesogenic units. The nature of the LC phase proves to be dependent on the mesogen content. Below a certain content the smectic C phase vanishes, and the polymer becomes cypotactic nematic. T-g, T-s,T-n, T-n,T-i and Delta H-s,H-n depend on the mesogen content, whereas Delta H-n,H-i is independent. No difference can be detected between the phase behaviour of homopolymers and ABA-triblock copolymers with a liquid crystalline B-block and 10 wt.-% polystyrene A-blocks.