In search of functional molecular materials and the study of their formation mechanism, we report the elucidation of a hierarchical step-by-step formation from monomer (Mn) to heptamer (Mn-7) to nonadecamer (Mn-19) satisfying the relation 1 + Sigma(n)6n, where n is the ring number of the Brucite structure using high-resolution electrospray ionization mass spectrometry (HRESI-MS). Three intermediate clusters, Mn-10, Mn-12, and Mn-14, were identified. Furthermore, the Mn-19 disc remains intact when dissolved in acetonitrile with a well-resolved general formula of [Mn-19(L)(x)(OH)(y)-(N-3)(36-x-y)](2+) (x = 18, 17, 16; y = 8, 7, 6; HL = 1-(hydroxymethyl)-3,5-dimethylpyrazole) indicating progressive exchange of N-3(-) for OH-. The high symmetry (R-3) Mn-19 crystal structure consists of a well-ordered discotic motif where the peripheral organic ligands form a double calix housing the anions and solvent molecules. From the formula and valence bond sums, the charge state is mixed-valent, [(Mn15Mn4III)-Mn-II]. Its magnetic properties and electrochemistry have been studied. It behaves as a ferrimagnet below 40 K and has a coercive field of 2.7 kOe at 1.8 K, which can be possible by either weak exchange between clusters through the anions and solvents or through dipolar interaction through space as confirmed by the lack of ordering in frozen CH3CN. The moment of nearly 50 N mu(B) suggests Mn-II-Mn-II are and Mn-III-Mn-III ferromagnetically coupled while Mn-II-Mn-III is antiferromagnetic which is likely if the Muni are centrally placed in the cluster. This compound displays the rare occurrence of magnetic ordering from nonconnected high-spin molecules.