Iron(II) octaethyltetraazaporphyrin has been discovered-to exist as two polymorphs at room temperature, alpha- and beta-Fe(OETAP). This has been established by X-ray powder diffraction and scanning electron microscopy. Both ac and de SQUID magnetometry show that the alpha phase is a soft molecular ferromagnet with T-Curie = 2.8 K. The beta phase possesses the same number of unpaired spins and a similar g value, but it does not order above similar to 1 K. Zero-field splitting is Likely competing with ferromagnetic coupling in this compound. Fe-57 Mossbauer spectroscopy has been used to support the local structural similarity between the two phases and to study the ferromagnetic transition. The isomorphous manganese analogue of alpha-Fe(OETAP), alpha-Mn(OETAP), expected to be a ferromagnet with a higher T-Curie, exhibits many characteristics of ferromagnetism, notably hysteresis at 1.8 K with H-coer = 2.5 kG and M-rem = 4 kemu-G/mol. However, in contrast to ferromagnetic alpha-Fe(OETAP), alpha-Mn(OETAP) shows strongly frequency-dependent ac susceptibility in the range from 1 to 1000 Hz, indicating that it exists in a spin-glass-like state. This result underscores the need for frequency-dependent ac magnetometry to fully characterize ferromagnetic molecular materials.