Structures that include interconnects and methods of forming structures that include interconnects. A first interconnect is formed in a first trench in an interlayer dielectric layer, and a second interconnect in a second trench in the interlayer dielectric layer. The second interconnect is aligned along a longitudinal axis with the first interconnect. A dielectric region is arranged laterally arranged between the first interconnect and the second interconnect. The interlayer dielectric layer is composed of a first dielectric material, and the dielectric region is composed of a second dielectric material having a different composition than the first dielectric material.