Triblock co- and terpolymers with orders of blocks synthetically difficult to be obtained by means of sequential living anionic polymerization were successfully synthesized by developing a new methodology combining living anionic block copolymers with a specially designed linking reaction. The synthesized polymers involve ACB and BAC triblock terpolymers and ABA', ACA', and BCB' triblock copolymers, where A, B, and C are polystyrene, poly(2-vinylpyridine), and poly(methyl methacrylate) segments, respectively. The A', A as well as B, B' are identical in polymer structure but different in molecular weight All of them are new type triblock ter- and copolymers with well-defined structures, i.e., predictable molecular weights, compositions, and narrow molecular weight distributions. Transmission electron microscopic studies were performed on bulk morphologies of ACB and BAC triblock terpolymers to exemplarily investigate the influence of changing block sequence,and, thus changing interfaces. Although both terpolymers showed the tendency to form a lamella-lamella morphology, ACB revealed unusually strongly curved lamellae and BAC even undulated lamellae.