We report on the synthesis of a new praseodymium molybdenum borate under high-pressure/high-temperature conditions. The new compound with the sum formula Pr3Mo4B6O24(OH)3 crystallizes acentrically in the monoclinic space group Cm displaying a new structure type. The structure was solved via single-crystal structure determination. Additionally, the proposed structural model was confirmed by powder X-ray diffraction, second harmonic generation measurement, and single-crystal infrared and Raman spectroscopic investigation.