New Haldane gap compounds with S=1 have been characterized by single-crystal X-ray analyses and magnetic measurements. From these results, it has been found that the magnitude of the Haldane gaps can be controlled by substituting the bridging groups and in-plane ligands. The magnetic measurements of quasi-one-dimensional halogen-bridged binuclear Ru complexes with S=3/2. Ru2(CH3COO)4X (X=Cl, Br and 1) have revealed that the Br- and I-bridged compounds show one-dimensional antiferromagnetic interactions but no spin-Pelerls transition over the temperature range measured, while the C1-bridged compound shows no magnetic interaction among binuclear RU2units through the bridging Cl−ions along the chain but spin-crossover behavior between S=3/2 and 1/2 in the binuclear Ru2unit. The oxalato-bridged Fe2+compound with S=2, Fe(ox).2Hz0 has no Haldane gap but shows metamagnetism under the high magnetic field.