Manganese silicalite-2 was synthesized at high pH using the molecular cluster Mn12O12(O2CCH3)(16) as a Mn source. The silicalite-2 (ZSM-11) materials were synthesized using 3,5-dimethyl-N,N-diethylpiperdinium hydroxide as a. structure-directing agent to produce phase-pure ZSM-11 materials. No precipitation of manganese hydroxide was observed, and synthesis resulted in the incorporation of up to 2.5 mol % Mn into the silicalite-2 with direct substitution into the framework verified by the linear relationship between the unit cell volume and loading. The Mn is reduced to Mn-II during hydrothermal synthesis and incorporated into the silicalite-2 framework during calcination at 500 degrees C. Further calcination at 750 degrees C does not affect the crystallinity but oxidizes essentially all of the Mn-II to Mn-III in the framework. The large difference in oxidation temperatures between the II and III oxidation states provides a means of producing relatively pure manganese(II) and manganese(Ill) silicalite-2 materials for applications such as catalysis.