Crystals of the MnxBa12(BO3)8-2xF8x phase were grown from a high-temperature solution. This new fluoride borate is built of positively charged [Ba12(BO3)6]6+ blocks, the so-called "anti-zeolite" pattern. Using X-ray single-crystal diffraction, the bulk atomic arrangement in the centrosymmetric tetragonal unit cell in I4/mcm could be elucidated. Crystals of the (MnF6)4- group-containing solid solution MnxBa12(BO3)8-2xF8x are dark brown in color in contrast to the differently colored crystals of (LiF4)3- group-containing "anti-zeolite" LiBa12(BO3)7F4 (P42bc). According to the electron spin resonance and optical spectroscopic investigation, the absorption spectrum of LiBa12(BO3)7F4 crystals results from the absorption of light by both exciton and free charge carriers and can be tuned by varying the initial composition of the high-temperature solution.