AbstractNanorods as building blocks are promising to construct functional superstructures. A paramagnetic Fe3O4‐based composite nanorod is large‐scale synthesized from the poly(2‐vinylpyridine) (P2VP) side chain grafted polymer bottlebrush by electrostatics‐mediated intramolecular crosslinking via metallic coordination. Ultrasonication‐assisted fracturing of the composite nanorod derives the corresponding A2‐type composite nanorods whose two ends are active with the metallic coordinated P2VP exposed. The active ends are prone to connection upon feeding ligands (acidic or alkaline) or metallic ions to trigger the organization of the A2‐type nanorods toward functional superstructures. Their microstructure is tunable from linear nanowires to branches, which is dependent on the valent state of the assistant chemicals. The report method is easily extended to derive a family of A2‐type active nanorods with varied compositions and functions which are capable to organize functional nanomaterials with tunable microstructure.