Sensitization with dyes is the most promising option to narrow the band gap and improve visible-light absorption of TiO2. As ideal structure and reaction models of TiO2, titanium oxo clusters (TOCs) with exact crystal structure are beneficial for further understanding the structure–property relationship of TiO2. Most reports mainly focus on the synthesis and properties of TOCs, but research on the band-gap tuning of TOCs at the large range of 3.7–2.0 eV by chromophore ligands (CLs) has been lacking. Herein, six new Ti6-core-based TOCs (Ti6-TOCs) were successfully synthesized by using CLs in a simple and general approach. Each Ti6-TOC structure contains two Ti3(μ3-O) units featuring a flat or pyramidal mode as building blocks. Five Ti6-core structure types were present among the six Ti6-TOCs, which enriched the family of hexanuclear TOCs. To be noted, the band-gap values were tuned at a wide range of 3.41–1.98 eV by controlling the type and number of the CLs 2-hydroxypyridine, salicylaldoxime, and catechol in the structure. Density functional theory calculation revealed that the lowest-energy bands of these Ti6-TOCs are attributed to the CL-to-TiO core charge-transfer bands. This work provides a precise and wide-ranged band-gap tuning method for TOCs. Additionally, the six Ti6-TOCs exhibit good photocurrent response.