We have measured the electrical resistivity of La 4BaCu 5O 13 and La 5SrCu 6O 15-based compounds down to 39mK and 16mK, respectively, without observing superconductivity. When the resistivity ϱ − ϱ 0 was proportional to T γ, the exponent γ ranged from 1.18 to 1.83 for these compounds, where ϱ 0 is residual resistivity and T is temperature. It was ascertained from our measurements down to the mK range that these compounds were not superconducting because of a three-dimensional network of CuO 5 units.