Ladder-like aromatic diketones (LADK), which possess a coplanar π-extended geometry, a high electron deficiency as well as various attractive optoelectronic properties, are demonstrated as the promising candidates in building small-molecule organic electron-transporting materials, yet reports on direct integration of these structural motifs into n-type polymers are rarely accessed. Herein, it is demonstrated that a possibility of realizing unipolar n-type characteristics of such acceptor system by developing two novel donor-acceptor type polymers, in which the newly developed LADK unit, named as 3,8-bis(2-decyltetradecyl)-5,10-difluoro-s-indaceno[1,2-b:5,6-b′] dithiophene-4,9-dione (FIDTO-R), is adopted as the acceptor segments. The resulting polymers present deep-lying unoccupied molecular orbital levels (as low as −3.84 eV), compact π-π stacking (d-spacing, ≈3.57 Å) coupled with uniform nanofiber-like surface morphology. All these factors contribute to excellent unipolar n-type characteristics with high electron mobilities of 0.27 and 1.01 cm 2 V −1 s −1 , together with high inverter gain values of 141 and 80, respectively. The recorded values are among the best in n-type polymer field-effect transistors and associated inverter circuits. These findings unambiguously reveal that the as-prepared FIDTO-R and its analog LADK derivatives are another type of excellent building blocks for the construction of high-mobility n-type polymers.