The short 1,2-polybutadiene center block of the ternary polystyrene-block-polybutadiene-block-poly(methyl methacrylate) S45B6M49225-triblock copolymer (subscripts indicating the weight fractions and the superscript indicating the total molecular weight in kg/mol) has been selectively modified by complexation with metal complexes of two different transition metals, namely Pd and Fe. These modifications cause significant variations in the microphase morphology. The original ls-morphology (spheres at lamellar interphase) belonging to the lamellar class changes via a cocontinuous morphology in the case of the Pd-complex to a morphology belonging to the cylindrical class for the Fe-complex.