A novel double liquid crystalline (LC) block copolymer (BCP) composed of poly[omega-(4'-methoxybiphenyl-4-yloxy)hexyl methacrylate] (PMBHMA) and poly{2,5-bis[(4-meth-oxyphenyl)oxycarbonyl]styrene} (PMPCS) was designed and successfully synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Whereas PMBHMA is a conventional side-chain LC (SCLC) polymer, PMPCS is a typical mesogen-jacketed I,C polymer, which can serve as rod after it forms columnar LC (Phi) phase. Therefore, the PMBHMA-b-PMPCS is an SCLC-rod BCP. The phase structures and transitions of the PMBHMA-b-PMPCS synthesized with a PMPCS volume fraction of similar to 49% were investigated using various techniques including thermal analysis and X-ray scattering and diffraction methods. A microphase-separated lamellar morphology was identified for this SCLC-rod sample. The Phi phase of the PMPCS block with the rod direction perpendicular to the interface remained unchanged and impacted the LC transitions of PMBHMA blocks greatly. We found that the smectic A phase of the PMBHMA disappeared, and meanwhile, its nematic phase got stabilized over a wide temperature range. At low temperatures, small smectic E domains with homogeneous orientation formed in the PMBHMA block domains. Our work demonstrates that the confinement imposed by the rod block and dimension commensurability of the ordered structures are indeed crucial for SCLC-rod BCPs.