Sequential infiltration synthesis (SIS), combining stepwise molecular assembly reactions with self-assembled block copolymer (BCP) substrates, provides a new strategy to pattern nanoscopic materials in a controllable way. The selective reaction of a metal precursor with one of the pristine BCP domains is the key step in the SIS process. Here we present a straightforward strategy to selectively modify self-assembled polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) BCP thin films to enable the SIS of a variety of materials including SiO(2), ZnO, and W. The selective and controlled interaction of trimethyl aluminum with carbonyl groups in the PMMA polymer domains generates Al-CH(3)/Al-OH sites inside the BCP scaffold which can seed the subsequent growth of a diverse range of materials without requiring complex block copolymer design and synthesis.