Single-phase polycrystalline samples and single crystals of the complex boride phases Ti₈Fe₃Ru₁₈B₈ and Ti₇Fe₄Ru₁₈B₈ have been synthesized by arc melting the elements. The phases were characterized by powder and single-crystal X-ray diffraction as well as energy-dispersive X-ray analysis. They are new substitutional variants of the Zn₁₁Rh₁₈B₈ structure type, space group P4/mbm (no. 127). The particularity of their crystal structure lies in the simultaneous presence of dumbbells which form ladders of magnetically active iron atoms along the [001] direction and two additional mixed iron/titanium chains occupying Wyckoff sites 4h and 2b. The ladder substructure is ca. 3.0 Å from the two chains at the 4h, which creates the sequence chain–ladder–chain, establishing a new structural and magnetic motif, the scaffold. The other chain (at 2b) is separated by at least 6.5 Å from this scaffold. According to magnetization measurements, Ti₈Fe₃Ru₁₈B₈ and Ti₇Fe₄Ru₁₈B₈ order ferrimagnetically below 210 and 220 K, respectively, with the latter having much higher magnetic moments than the former. However, the magnetic moment observed for Ti₈Fe₃Ru₁₈B₈ is unexpectedly smaller than the recently reported Ti₉Fe₂Ru₁₈B₈ ferromagnet. The variation of the magnetic moments observed in these new phases can be adequately understood by assuming a ferrimagnetic ordering involving the three different iron sites. Furthermore, the recorded hysteresis loops indicate a semihard magnetic behavior for the two phases. The highest H_c value (28.6 kA/m), measured for Ti₇Fe₄Ru₁₈B₈, lies just at the border of those of hard magnetic materials.