4,4′-(Disulfanediyl)dibutanoic acid (dtba) and 4,4′-bipyridine (4,4′-bpy) crystallize in an 1:1 ratio, leading to the title co-crystal with composition C₈H₁₄O₄S₂·C₁₀H₈N₂. A distinctive feature of the crystal structure is the geometry of the dtba moiety, which appears to be stretched [with a 9.98 (1) Å span between outermost carbons] and acts as an hydrogen-bonding connector, forming linear chains along [-211] with the 4,4′-bpy moiety by way of O–H⋯N hydrogen bonds and C–H⋯O interactions. The influence of the molecular shape on the hydrogen-bonding pattern is analysed by comparing the title compound and two other 4,4′-bpy co-crystals with closely related molecules of similar formulation but different geometry, showing the way in which this correlates with the packing arrangement.