Among many properties of cyclic block copolymers, the notable domain spacing (d-spacing) reduction offers nonlinear topology as an effective tool for developing block copolymers for nanolithography. However, the current consensus regarding the topology-morphology correlation is ambiguous and in need of more studies. Here we present the morphological investigation on nanoscale films of cyclic and tadpole-shaped poly(n-decyl glycidyl ether-block-2-(2-(2-methoxyethoxy)ethoxy)ethyl glycidyl ether)s and their linear counterpart via synchrotron grazing-incidence X-ray scattering. All copolymers form phase-separated nanostructures, in which only the nonlinear copolymers form highly ordered and unidirectional nanostructures. Additionally, d-spacings of cyclic and tadpole-shaped block copolymers are 49.3-53.7% and 25.0-32.5% shorter than that of their linear counterpart, respectively, exhibiting greater or comparable d-spacing reductions against the experimentally and theoretically achieved values from the literature. Overall, this study demonstrates that cyclic and tadpole topologies can be utilized in developing materials with miniaturized dimensions, high structural ordering, and unidirectional orientation for various nanotechnology applications.