Herein,　we　report　a　ball-milling　metal-free　polymerization　to　synthesize　isoindigo-derived　conjugated　polymers　in　the　presence　of　readily　available　tris(diethylamino)phosphine.　The　resulting　polymers　possess　comparable　molecular　weights　and　similar　optical　and　electronic　properties　relative　to　their　counterparts　prepared　via　the　solvent　method.　This　new　solvent-free　and　metal-free　polymerization　method　can　be　performed　under　ambient　conditions.　©　2023　The　Royal　Society　of　Chemistry.