All-polymer solar cells (all-PSCs) can offer unique advantages for applications in flexible devices,a nd naphthalene diimide (NDI)-based polymer acceptors are the widely used polymer acceptors.H owever,t heir power conversion efficiency (PCE) still lags behind that of state-of-the-art polymer solar cells,d ue to lowl ight absorption, suboptimal energy levels and the strong aggregation of the NDI-based polymer acceptor.H erein, ar hodanine-based dye molecule was introduced into the NDI-based polymer acceptor by simple random copolymerization and showed an improved light absorption coefficient, an up-shifted lowest unoccupied molecular orbital level and reduced crystallization. Consequently,a dditive-free all-PSCs demonstrated ah igh PCE of 8.13 %, which is one of the highest performance characteristics reported for all-PSCs to date.T hese results indicate that incorporating ad ye into the n-type polymer gives insight into the precise design of high-performance polymer acceptors for all-PSCs.Polymer solar cells (PSCs) have made considerable progress during the past two decades. [1][2][3] Thep ower conversion efficiency (PCE) of single-junction fullerene-based PSCs has been attained over 11 %. [4] Recently,P CEs exceeding 13 % have been achieved with proper molecular designs of wideband-gap polymer donors and fused-ring electron acceptors. [5][6][7] Regarding fullerene-based and fused-ring electron acceptor-based devices,a ll-polymer solar cells (all-PSCs) composed of ac onjugated polymer donor and an n-type conjugated polymer offer unique attractions due to their special advantages of morphological stability and flexibility. [8][9][10][11][12][13][14][15][16] Forp ractical applications,t he morphological stability of the all-PSCs against the mechanical and thermal stresses is beneficial for applications in flexible large-scale and stable devices.Although the PCE of all-PSCs has reached 10 %, [15] the performance of all-PSCs still lag behind that of state-of-theart small-molecule-based devices,o wing to the lack of suitable n-type polymer acceptors.T od ate,t he number of polymer acceptors developed for all-PSCs are limited, and only five studies have reported all-PSCs with ap hotovoltaic efficiency over 8% for ab inary system.