In this study, parallelogram-like macrocyclic supramolecular metallacycles [Pd₆(bpy)₆(L¹)₄](PF₆)₈ (1a) and [Pd₆(bpy)₆(L²)₄](PF₆)₈ (2a), where HL¹=1-(1H-pyrazole-4-yl)-4-(4-pyridyl)benzene, HL²=9-(1H-pyrazole-4-yl)-10-(4-pyridyl)anthracene, and bpy=2, 2'-bipyridine, are synthesized by reacting aryl pyrazole pyridine ligands with dipalla-dium corners in aqueous solutions via metal-directed hierarchical self-assembly. The structures of the supramolecular Pd parallelograms are confirmed through single-crystal X-ray diffraction. Notably, the two parallelogram metallacycles can be used as"turn-on"fluorescence sensors to detect HSO₃^- through a disassembly mechanism. In addition, the 1a-based sensor shows selective detection of HSO₃^- without interference from other anions. The detection limit was as low as 0.131 μmol·L^-1. Furthermore, complex 1a presented the semiquantitative visual detection ability for HSO₃^- in the test trip mode via fluorescence changes.