AbstractThe phase behaviour of methacrylic side chain liquid‐crystalline (LC) copolymers, with a spacer‐decoupled mesogen in one comonomer and a methyl (MMA) or stearyla (SMA) substituent in the other comonomer, was studied. The mesogen is of the phenyl benzoate type and has a methoxy end group. The LC homopolymer (PLC) has a smectic and a nematic phase. The comonomers MMA and SMA destabilize the LC phase. This effect is compared to the destabilisation caused by end groups in oligomers of PLC. The SMA side chains crystallize so that the SMA copolymers assume a smectic‐crystalline bilayer structure. Finally, it is shown that the order of the copolymers affects their mutual miscibility.