Solid-state metal oxides with three-dimensional organization of catalytic components at nano-scale have high potential as catalysts for chemical conversion because the materials could provide unique reaction fields at catalytic active sites which are particularly important for multi-step catalytic reactions like selective oxidation. Here, crystalline Mo₃VO_x, a new type complex metal oxide catalyst, is introduced as a prominent example of solid-state metal oxides with three-dimensional organization. The material has a network arrangement of pentagonal units as a structure building block with the formation of 6-member ring channel and 7-member ring channel in its crystal structure. The material showed an outstanding catalytic performance for both selective oxidations of ethane to ethene and of acrolein to acrylic acid, revealing the importance of these structures for the catalytic oxidation activity. The outstanding catalytic performance for the reactions is ascribed to octahedra clusters isolated in the pentagonal unit network and to microporous property of the 7-member ring channel.