This paper describes an original and facile polyol-mediated solvothermal synthesis of elliptical iron glycolate nanosheets (IGNSs) combined with precursor thermal conversion into γ-Fe₂O₃ and α-Fe₂O₃/γ-Fe₂O₃ porous nanosheets (PNSs), α-Fe₂O₃ nanochains (NCs), and elliptical Fe₃O₄ nanorings (NRs). The IGNSs were produced via the oxidation–reduction and co-precipitation reactions in the presence of iron(III) salts, ethylene glycol, polyethylene glycol, and ethylenediamine. Control over Fe³⁺ concentration, temperature, and time can considerably modulate the size and phase of the products. The IGNSs can be transformed to γ-Fe₂O₃ and α-Fe₂O₃/γ-Fe₂O₃ PNSs, α-Fe₂O₃ NCs, and elliptical Fe₃O₄ NRs by heat treatment under various annealing temperatures and ambiences. The PNSs and NCs exhibited high soft magnetic properties and coercivity, respectively. Visible-light photocatalytic activity toward RhB in the presence of H₂O₂ by PNSs and NCs was phase-, S_BET, size-, porosity-, and local structure-dependent, following the order: α-Fe₂O₃ NCs > α-Fe₂O₃/γ-Fe₂O₃ PNSs > γ-Fe₂O₃ PNSs > IGNSs. In particular, α-Fe₂O₃/γ-Fe₂O₃ PNSs possessed significantly enhanced photocatalytic activity with good recyclability and could be conveniently separated by an applied magnetic field because of high magnetization. We believe that the as-prepared α-Fe₂O₃/γ-Fe₂O₃ PNSs have potential practical use in waste water treatment and microwave absorption.