The experimental work began with the interphase between well-known materials: the perovskite BaRuO3, the pyrochlore-type Y2Ru2O7, and Y2Si2O7 which was chosen to increase potential structural complexity by introducing the tetrahedral silicon coordination environment. This interphase is placed within the five-dimensional Ba-Y-Si-Ru-O chemical space that so far has no quinary phases reported in the inorganic compound databases. However, within the lower fourdimensional borders of this space, there have been reports on the perovskites Ba2YRuO6, Ba3YRu2O9, and BaY0.33Ru0.67O3 for the Ba-Y-Ru-O space, and the silicates Ba9Y2[SiO4]6, 32 BaY2Si3O10, BaY4Si3[Si2O7]O10, and BaY16Si4O33 obtained by conventional solid state reactions, which proves that there is potential reactivity of the components. Beginning with solid state syntheses at compositions that span the phase diagrams, unidentified patterns were observed that later led to the discovery of two compounds (referred to as Phase A and B throughout the text). In both cases, no ruthenium was incorporated into the structures, and the phases further expand the knowledge of an already populous BaO-Y2O3-SiO2 phase field (Table ). Phase A was isolated via iterative exploratory synthesis based on elemental analysis, while Phase B was harder to locate since it is situated near the edge of the glass forming region in the BaO-Y2O3-SiO2 system and was isolated with the aid of the automated phase isolation software (Probabilistic Isolation of Crystalline Inorganic Phases, or PICIP) that uses overall composition and the diffraction-determined ratios of known phases to direct the selection of compositions in subsequent synthetic reactions (see Figure ). The structures of these new phases were solved directly using continuous rotation electron diffraction (CRED) and refined against combined high-resolution synchrotron X-ray diffraction (SPXRD) and time-of-flight neutron diffraction data (TOF). The complementary exploration routes leading to these two phases, their structures and properties are described herein.