A new double betaine 1,1?-(propane-1,3-diyl)dipyridinium-4-carboxylate L has been synthesized. Reaction of 1,1?-(propane-1,3-diyl)dipyridinium-4-carboxylate tetrahydrate 1 with Co(ClO4)2?6H2O leads to the formation of a new Co(II) coordination compound, namely [Co(H2O)6]?2H2O?2L?2ClO4 2. The crystal structures of 1 and 2 have been determined by single-crystal X-ray diffraction method. Crystal data for 1: monoclinic, space group C2/c, a = 18.945(4), b = 7.700(2), c = 11.888(2) ?, β = 101.67(3)°, V = 1698.3(6) ?3, Z = 4, F(000) = 760.0, Dc = 1.402 g/cm3, the final R = 0.0607 and wR = 0.1607 for 950 observed reflections (I > 2σ(I)); and those for 2: monoclinic, space group P21/c, a = 17.982(1), b = 15.879 (1), c = 7.0716(5) ?, β = 100.675(1)°, V = 1984.3(3) ?3, Z = 4, F(000) = 1010.0, Dc = 1.631 g/cm3, the final R = 0.0316 and wR = 0.0896 for 3784 observed reflections (I >2σ(I)). Crystal structure analysis indicates that in 1, molecules of L in a “V-shaped” conformation are linked to chains sustained by O–H···O hydrogen bonds between carboxylate groups and solvent water molecules. The chains are joined by O–H···O and C–H···O hydrogen bonds to further expand into a three-dimensional structure. For 2, molecules of L in a “Z-shaped” conformation are linked by hydrogen bonds between carboxylate groups and aqua ligands to form a chain of loops running down the b axis. The (2D→2D) polythreading in compound 2 represents the mode of parallel interpenetration of 2D sheets, having polyrotaxane character. A new double betaine 1,1? - (propane-1,3-diyl) dipyridinium-4-carboxylate tetrahydrate has been synthesized. 1 with Co (ClO4) 2 · 6H2O leads to the formation of a new Co (II) coordination compound, namely [Co (H2O) 6] · 2H2O · 2L · 2ClO4 2. The crystal structures of 1 and 2 have been determined by a = 18.945 (4), b = 7.700 (2), c = 11.888 (2)?,? = 101.67 (3) V = 1698.3 (6)? 3, Z = 4, F (000) = 760.0, Dc = 1.402 g / cm3, the final R = 0.0607 and wR = 0.1607 for 950 observed reflections (I> 2σ (I) ; and those for 2: monoclinic, space group P21 / c, a = 17.982 (1), b = 15.879 (1), c = 7.0716 (5) (3) Z = 4, F (000) = 1010.0, Dc = 1.631 g / cm3, the final R = 0.0316 and wR = 0.0896 for 3784 observed reflections (I> 2σ (I) , molecules of L in a “V-shaped” conformation are link ed to chains sustained by O-H ··· O hydrogen bonds between carboxylate groups and solvent water molecules. The chains are joined by O-H ··· O and C-H · O hydrogen bonds to further expand into a three -dimensional structure. For 2, molecules of L in a “Z-shaped” conformation are linked by hydrogen bonds between carboxylate groups and aqua ligands to form a chain of loops running down the b axis. The (2D → 2D) polythreading in compound 2 represents the mode of parallel interpenetration of 2D sheets, having polyrotaxane character.