The incorporation of 2,1,3-benzothiadiazole units within the arms of a trigonal quarterfluorene–truxene star-shaped system leads to a monodisperse material with stable multi-electron p- and n-doped states and highly efficient yellow electrogenerated chemiluminescence (ECL). The quantum yield for ECL is 7 times greater than that of the common blue ECL emitter 9,10-diphenylanthracene (DPA).