AbstractThe preparation and X‐ray crystal structures of the adducts of 10‐thiabenzo‐15‐crown‐5 and 10‐selenabenzo‐15‐crown‐5 with PdCl2are reported. [PdCl2(C14H20O4S)2] (1): orthorhombic, space groupPbcawith cell dimensions ofa=17.285(5),b=8.354(3),c=21.689(4) Å,V=3131.9 Å3, Z=4;R=0.0330 for 2301 reflections withI>3σ(I), [PdCl2(C14H20O4Se)2] (2): monoclinic, space groupP21/nwith cell dimensions ofa=18.928(4),b=8.912(3),c=9.813(2) Å, β=96.90(2)°, V=1643.4 Å3,Z=2;R=0.0289 for 2617 reflections withI>3σ(I), Both complexes are monomeric, square‐planar palladium(II) compounds with the Pd(II) ion situating on a crystallographic inversion centre, and the crown ligands all adopt the axial coordination with the Pd–‐S bond of 2.3233(7) Å and the Pd–‐Se bond of 2.4357(3) Å. Their complexing c