The adsorption of perylenediimide (PDI)-based dye compounds (BrPDI, BrGly, and BrAsp) on the defect-free unreconstructed (UR) rutile TiO2(110) surface has been studied using total energy pseudopotential calculations based on density functional theory. All dye molecules form moderate chemical bonds with the defect-free UR rutile (110) surface in the most stable adsorption configurations. Electronic structure analysis reveals that HOMO and LUMO levels of the adsorbed dye molecules appear within the band gap and conduction band region of the UR surface, respectively. The effect of model slab thickness on interaction strength between the dye and the UR surface has also been examined. Unlike on four-layer slabs, BrGly and BrAsp molecules are dissociatively adsorbed on the three-layer slabs. Interaction between the BrPDI and partially reduced UR rutile (110) as well as the platinized UR surface has also been considered to figure out the effects of 0 vacancy and previously adsorbed Pt clusters on the binding, electronic, and structural properties of the dye-surface system. The BrPDI molecule prefers to bind to the O vacancy site of the partially reduced URsurface. The existence of the small Pt-n (n = 1, 3, and 5) clusters on the reduced UR surface does not significantly alter the binding strength between the surface and BrPDI.