Six crystalline polyoxo-titanium clusters (PTCs) derived from oximes, namely, Ti-4(mu(4)-O)(OMe)(6)(L1)(4) (PTC-125; H(2)L1 = salicylaldoxime), H[Ti-5(mu(2)-O)(mu(3)-O)(2)(OMe)(3)(L1)(6)] (PTC-126), Ti-6(mu(2)-O)(mu(3)-O)(2)(OiPr)(10)(OAc)(2)(L2)(2) (PTC-127; H(3)L2 = salicylhydroxamic acid; HOAc = acetic acid), Ti-7(mu(3)-O)(2)(OEt)(18)(L2)(2) (PTC-128), Ti-12(mu(2)-O)(4)(mu(3)-O)(4)(OEt)(20)(L2)(4) (PTC-129), and Ti-18(mu(2)-O)(10)(mu(3)-O)(8)(mu(4)-O)(2)(OEt)(30)(L3)(2) (PTC-130; HL3 = acetoxime) have been solvothermally synthesized and structurally characterized. Compared with the reported solid-state monomer, dimer, trimer, and tetramer titanium oximes, these compounds possess high nuclearity structures in the range Ti-4, Ti-5, Ti-6, Ti-7, Ti-12, and Ti-18 as a result of the presence of oxo bridges. Even though three examples of tetranuclear and hexanuclear derivatives have been documented, PTC-130 with a centrosymmetric Ti-18 cluster core represents the currently highest PTC compound in the oxime system. In addition, Ti/oximate ratio by solvothermal synthesis in this work possessed a broad range from 0.83:1 to 9:1, different from the constant ratio of 1:1 in the reported ones. According to the solid-state UV-vis diffuse reflectance measurement, the existence of oxime ligands largely enhanced their visible light harvest. Furthermore, their photocurrent response properties are also studied