Metallation of the cavitand with Mn(II) was carried out by reacting the former with two equivalents of LiHMDS in anhydrous THF, followed by an addition of a small excess of Mn(OTf)2(MeCN)2 (Scheme 2). Soon after the addition, a very thin light purple powder began to precipitate from the reaction solution. This product was identified as the Mn(II)metallocavitand 8, based on the molecular ion mass of [M+H] + = 1408.3250 amu, consistent with its empirical formula, detected by ESI-HRMS. This compound was nearly insoluble in THF or MeCN, but could be easily dissolved in chlorinated solvents, such as DCM, which allowed for the measurement of its effective magnetic moment using the Evans method. The obtained value of μeff = 5.58 BM was somewhat lower than the theoretical spin only moment for an S=5/2 system (5.91 BM), but still within the typical range observed in high-spin Mn(II) complexes (5.47-6.01 BM). 70