It′s all about polymers: All‐polymersolarcells (all‐PSCs) based on six perylenediimide containing polymers (PX–PDIs) as acceptor materials and two polythiophene derivatives (P3HT and PT1) as donor materials were investigated systematically (see picture). The highest power‐conversion efficiency (PCE) of all‐PSCs was 2.23 %, one of the highest PCEs of polymer/polymer blend photovoltaic devices reported