One-dimensional lanthanice-transition heterometallic chains of squares, {LnNi(2)L(3)(HL)(DMF)(4)(CIO4)(4).S}(infinity) (Ln = Gd and Tb; HL is the Schiff base obtained by the condensation of 2-pyridylaldehyde with isonicotinic hydrazide N-oxide; S = solvent) and {LnNi(2)L(4)-(DMF)(4)(CIO4)(3).S}(infinity) (Ln = Dy; S = solvent), were synthesized by self-assembly between well-designed orthogonal metalloligands [Ni-(HL)L](+) and the Ln(III) ions, which act as the bridging units and nodes, respectively.