Porous solids have attracted a great amount of attention in the last few years because of not only their interesting crystal structures but also their potential applications in catalysis, ion-exchange and sorption. In this dissertation research, the exploratory synthesis of novel crystalline microporous materials was studied in detail. The types of open frameworks of interest include organically templated metal phosphates and metal-organic hybrid frameworks. A number of new compounds were prepared under mild hydro- or solvo-thermal conditions, and their crystal structures were carefully determined by single crystal and powder X-ray diffraction techniques. For many reactions, a careful control of reaction parameters (temperature, pH, reactant ratio, etc.) was required to discover an ideal synthetic condition for the desired product. The studies of metal phosphates resulted in the synthesis of new isomorphous scandium and indium fluorophosphates. Their structures were characterized in detail by single crystal X-ray diffraction as well as solid-state magic angle spinning NMR spectroscopy. In the case of metal-organic framework compounds, a wide variety of compounds were synthesized using various organic ligands including aromatic dicarboxylates and polyazaheterocycles. They exhibit diverse structures from 2-dimensional layers to 3-dimensional open frameworks. For those containing transition metal ions (Co²⁺ and Ni ²⁺), their magnetic properties were characterized by measuring susceptibilities. Some metal-organic frameworks were examined for their potential applications as gas storage materials. The nitrogen and hydrogen sorption measurements were carried out to estimate the surface area and the hydrogen storage capacity. The findings from the sorption studies gave some insights to the enhancement of H₂ uptake of metal-organic frameworks. It was found that high hydrogen sorption capacity does not solely depend on large pore size and surface area. Other factors, such as optimal pore size and coordinatively unsaturated metal centers, also play an important role for the attainment of greater H₂ sorption capacity in metal-organic frameworks.