A new organically templated uranyl molybdate [C3H9NH+]4[(UO2)3(MoO4)5] was prepared by a hydrothermal method at 220 °C. The compound is monoclinic, Сс, a = 16.768(6), b = 20.553(8), c = 11.897(4) Å, β = 108.195(7), V = 3895(2) Å3, R1 = 0.05. The crystal structure is based upon [(UO2)3(MoO4)5]4− uranyl molybdate layers. The isopropylammonium cations are located in the interlayer. The layers in the structure of [C3H9NH+]4[(UO2)3(MoO4)5] are considered as modular architectures. Topological analysis of layers with UO2:TO4 ratio of 3:5 (TVI = S, Cr, Se, Mo) was performed. Modular description is employed to elucidate the relationships between different structural topologies of [(UO2)3(TO4)5]4− layers and inorganic uranyl-based nanotubules. The possible existence of uranyl molybdate nanotubules is discussed.