Description 2-Chloromethyl-2,3-dihydrothieno[3,4-b]-1,4-dioxine (EDOT-Cl) can be prepared by reacting 3,4-dimethoxythiophene with 3-chloro-1,2-propanediol via transesterification. The six-memebered ring of the molecule exhibits twisted conformation. It acts as an intermediate during the multi-step synthesis of poly(sulfobetaine-3,4-ethylenedioxythiophene) (PSBEDOT), a conjugated polymer.2-Chloromethyl EDOT is a key building block for the incorporation of EDOT (3,4-ethylenedioxythio-phene) into copolymers.It may be used in the synthesis of the following EDOT derivatives:2-[((6-hexyloxy-9,10-anthraquinone)-2-yl)oxymethyl]-2,3-dihydrothieno[3,4-b][1,4]dioxine (AQ-EDOT)2-[(N′-(10-nonadecyl)perylene-3,4,9,10-biscarboximide-N-yl)4-phenoxymethyl]-2,3-dihydrothieno[3,4-b][1,4]dioxine (PTCDI-EDOT)2-[((6-hexyloxy-11,11,12,12-tetracyanoanthraquinodimethane)-2-yl)-oxymethyl]-2,3-dihydrothieno[3,4-b][1,4]dioxine (TCAQ-EDOT)