Biological systems feature controlled assembly of well-defined building blocks at different length scales. While major progress has been achieved in directing the assembly of synthetic molecular building blocks, controlled organization of nanostructured units into micro-and macroscale aggregates remains a challenge. Herein, we report the synthesis of well-defined nanostructured building blocks, cylindrical polymeric nanoparticles with controlled dimensions and inner surface chemistry, and their dynamic anisotropic organization into one-dimensional assemblies. Nanoparticle building blocks were produced by molecular templating of cylindrical bottle-brush copolymers featuring tricomponent side chains. The produced nanostructures were composed of a nonionic and bioinert polyethylene glycol (PEG) shell and stimuli-responsive poly(methacrylic acid) (PMA) chains grafted on the interior. We show that pH-dependent interactions between PMA chains exposed only at the nanoparticle ends lead to anisotropic end-to-end association of parent cylindrical nanostructures into elongated superstructures. (C) 2017 Wiley Periodicals, Inc.