<p>A series of layered praseodymium tellurite halides of the general formula [Pr_{12−<i>x</i>}(TeO₃)₁₂][M^I_4+3<i>x</i>X₁₆] (M = K, Rb, Cs; X = Cl, Br) and the compounds [Pr₁₂(TeO₃)₁₂][Cd₆Cl₂₄] and [SrPr₄(TeO₃)₄][Cl₆] were prepared by the crystallization from reactive halide fluxes at 825–850 °C. The structures of the new compounds were determined by single-crystal X-ray diffraction analysis. The applied synthetic protocol leads to a significant improvement of both the yield and quality of the crystals. The crystal structures of the majority of the new compounds consist of praseodymium tellurite blocks of the composition [Pr_{12−<i>x</i>}(TeO₃)₁₂] interleaving with metal halide counterparts of the composition [M^I_4+3<i>x</i>X₁₆] or [Cd₆X₂₄]. The crystal structure of the new tellurite chloride [SrPr₄(TeO₃)₄][Cl₆] contains [SrPr₄(TeO₃)₄] layers. This compound completes the [SrLn₄(TeO₃)₄][Cl₆] structural family (Ln = Ce, Pr, Nd, Sm). When using binary fluxes based on alkali halides, sodium cations were not incorporated in the final products; the reactions using fluxes composed of cadmium and alkali halides afforded [Pr₁₂(TeO₃)₁₂][Cd₆X₂₄] as the major products. The use of fluxes based on heavier alkali halides (K, Rb, Cs) resulted in the formation of products, the structures of which exhibit the partial cation ordering between the metal tellurite and metal halide layers. The polytypism and the application of the modular approach to the description, classification, and prediction of novel structures of layered rare-earth tellurite and selenite halides are discussed.</p>