The novel environment-friendly blue pigments Ba(TiO)(Cu_1－xLi_x)₄(PO₄)₄ (0 ≤ x ≤ 0.15), have been synthesized and their color properties investigated. By doping Li into the Cu sites, which causes distortion of the CuO₄ units, overlap of the charge transfer and d-d transition absorption bands has been successfully controlled. Among the samples, Ba(TiO)(Cu_0.90Li_0.10)₄(PO₄)₄ showed the most vivid blue hue, with a blueness value (－b*) of 57.6, a value comparable with that of the commercially available CoAl₂O₄ pigment (cobalt blue, －b* = 59.5). Moreover, the hue angle of this sample (H° = 268.7°) is close to the pure-blue hue angle (H° = 270°).