Two different zinc sulfite compounds have been prepared through the decomposition of pyrosulfite-dithionite ions in aqueous solution, viz. a dimeric complex, di-μ-sulfito-κ³O,O′:O″;κ³O:O′,O″-bis[(4,4′-dimethyl-2,2′-bipyridine-κ²N,N′)zinc(II)] dihydrate, [Zn₂(SO₃)₂(C₁₂H₁₂N₂)₂]·2H₂O, (I), which was solved and refined from a twinned sample, and an extended polymer, poly[[aqua(1,10-phenanthroline-κ²N,N′)zinc(II)]-μ₃-sulfito-κ²O:O′:O″-zinc(II)-μ₃-sulfito-κ³O:O:O′], [Zn₂(SO₃)₂(C₁₂H₁₀N₂)(H₂O)]_n, (II). In (I), the dinuclear Zn^II complex has a center of symmetry. The cation is five-coordinate in a square-pyramidal arrangement, the anion fulfilling a bridging chelating role. Compound (II) comprises two different zinc units, one being five-coordinate (square pyramidal) and the other four-coordinate (trigonal pyramidal), and two independent sulfite groups with different binding modes to the cationic centers.