NOVELTY - A polymer (1) containing fused selenophene ring is new.    USE - New polymer containing fused selenophene ring is used as charge-transport, semiconducting, electrically-conducting, photoconducting or light-emitting material in optical, electrooptical, electronic, electroluminescent or photoluminescent components or devices, such as organic FETs (OFET), thin-film transistors (TFT), integrated circuits (IC), logic circuits, capacitors, radio frequency identification (RFID) tags, devices or components, organic LEDs (OLED), organic light-emitting transistors (OLET), flat panel displays, backlights of displays, organic photovoltaic devices (OPV), solar cells, laser diodes, photoconductors, photodetectors, electrophotographic devices, electrophotographic recording devices, organic memory devices, sensor devices, charge injection layers, Schottky diodes, planarizing layers, antistatic films, conducting substrates, conducting patterns, electrode materials of batteries, alignment layers, biosensors, biochips, security markings, security devices, and components or devices used for detecting and discriminating DNA sequences (all claimed).    ADVANTAGE - The new polymer containing fused selenophene ring can be easily synthesized, and has high charge mobility, good processability, and excellent oxidative stability. The inclusion of selenopheno(3,2-b)thiophene into the polymer backbone results in an improvement of solubility of the polymer without affecting the ability of the polymer to self-organize and pack into highly ordered films.    DETAILED DESCRIPTION - A polymer of formula (1) containing fused selenophene ring, is new.    X1 or X2=Se, with the other being S or Se;    R1,R2=H, halogen, -CN, -NC, -NCO, -NCS, -OCN, -SCN, -C(=O)NR0R00, -C(=O)X0, -C(=O)R0, -NH2, -NR0R00, -SH, -SR0, -SO3H, -SO2R0, -OH, -NO2, -CF3, -SF5, P'-Sp-, optionally substituted silyl, or carbyl or hydrocarbyl with 1-40 carbon atoms which is optionally substituted and optionally comprises hetero atom(s);    P=polymerizable group;    Sp=spacer group or single bond;    X0=halogen;    R0,R00=H or optionally substituted 1-20C aliphatic or aromatic hydrocarbon group;    Ar=-CY'1=CY'2, -C?=C-, or optionally substituted mono- or polynuclear (hetero)aryl;    Y'1,Y'2=H, F, Cl or CN;    m=0, 1, 2, 3 or 4;and    n=greater than 10.