In this study, two heterometallic transition metal complexes with the formulas [CoK$_{4}(\mu _{10}$-C$_{6}$H$_{5}$O$_{7})_{2}$]$_{n}$ and [CdK($\mu _{8}$-C$_{6}$H$_{5}$O$_{7})(\mu $-H$_{2}$O)(H$_{2}$O)]$_{n}$ were synthesized as crystalline compounds. The structures of\textbf{ }these crystalline metal complexes were characterized by their spectral analyses (FT-IR, FT-Raman, thermal analysis, magnetic properties, and single-crystal X-ray diffraction techniques). According to the spectral data of the new metal complexes obtained, both metal complexes are in the monoclinic crystal system and in the P2$_{1}$/c and P2$_{1}$ space groups, respectively. The asymmetric unit of the metal complex [CoK$_{4}(\mu _{10}$-C$_{6}$H$_{5}$O$_{7})_{2}$]$_{n}$ contains one Co(II) ion, two potassium cations, and one (C$_{6}$H$_{5}$O$_{7})$ citrate ligand, whereas that of the asymmetric unit of the metal complex [CdK($\mu _{8}$-C$_{6}$H$_{5}$O$_{7})(\mu $-H$_{2}$O)(H$_{2}$O)]$_{n}$ contains one Cd(II) ion, one potassium cation, one (C$_{6}$H$_{5}$O$_{7})$ citrate ligand, and two coordinated water molecules.