NOVELTY - A polymer (P1) comprising polycyclic repeating units is new.    USE - As charge transport, semiconducting, electrically conducting, photoconducting or light emitting material in an optical, electrooptical, electronic, electroluminescent or photoluminescent device, or in a component of such a device, or in an assembly comprising such a device or component, where the device is selected from organic field effect transistors (OFET), thin film transistors (TFT), organic light emitting diodes (OLED), organic light emitting transistors (OLET), organic photovoltaic devices (OPV), bulk heterojunction (BHJ) OPV device or inverted BHJ OPV device, organic photodetectors (OPD), organic solar cells, laser diodes, Schottky diodes, and photoconductors, and the component is selected from charge injection layers, charge transport layers, interlayers, planarizing layers, antistatic films, polymer electrolyte membranes (PEM), conducting substrates, conducting patterns, and the assembly is selected from integrated circuits (IC), radio frequency identification (RFID) tags or security markings or security devices containing them, flat panel displays or its backlight, electrophotographic devices, electrophotographic recording devices, organic memory devices, sensor devices, biosensors and biochips (all claimed).    ADVANTAGE - The polymers (P1) have advantageous properties such as good processability, especially a high solubility in organic solvents, good structural organization and film-forming properties, high charge-carrier mobility, high on/off ratio in transistor devices, high oxidative stability and long lifetime in electronic devices. The polymers (P1) should be easy to synthesize, especially by methods suitable for mass production. The polymers (P1) have a low bandgap, which enable improved light harvesting by the photoactive layer and can lead to higher cell efficiencies, compared to prior art organic semiconducting (OSC) materials.    DETAILED DESCRIPTION - A polymer (P1) comprising polycyclic repeating units of formula (I) is new.    X and Y'=C(R1R2), C=C(R1R2), Si(R1R2), Ge(R1R2), C(=O) or NR1;    A1=group of formulae (ia)-(ih);    A2=group of formulae selected from 20 compounds as given in the specification e.g. group of formulae (ia)-(ih);    A3=group of formulae selected from 20 compounds as given in the specification e.g. group of formulae (ii)-(in);    V'=CR1 or N;    W'=O, S or Se;    R1 and R2=H, straight-chain, branched or cyclic 1-30C alkyl in which at least one CH2 group is optionally replaced by -O-, -S-, -C(=O)-, -C(=S)-, -C(=O)-0- -O-C(=O)-, -NR'o-, -SiR'oR'oo, -CF2-, -CHR'o=CR'oo-, -CY1=CY2- or -C?=C- in such a manner that O and/or S atoms are not linked directly to one another, and in which at least one H atom is optionally replaced by F, Cl, Br, I or CN, or denote aryl, heteroaryl, aryloxy or heteroaryloxy with 4 to 20 ring atoms which is optionally substituted, preferably by halo or by the aforementioned alkyl or cyclic alkyl groups;    Y1 and Y2=H, F, Cl or CN;    R'o and R'oo=H or optionally substituted 1-40C carbyl or hydrocarbyl, and preferably H or 1-12C alkyl.    Provided that A1, A2 and A3 do not at the same time denote a benzene ring. INDEPENDENT CLAIMS are included for the following:    (1) a mixture or polymer blend comprising the polymers (P1) and at least one compound or polymer having semiconducting, charge transport, hole/electron transport, hole/electron blocking, electrically conducting, photoconducting or light emitting properties;    (2) a formulation comprising the polymers, mixtures or polymer blends, and solvents, preferably organic solvents;    (3) new mono/polyarene based monomer of formula R7-(Ar1)a-U'-(Ar2)c-R8 (VIa) or R7-U'-(Ar1)a-U'-R8 (VIb); and    (4) preparation of the polymer (P1).    a and c=0-2;    U'=unit of formula (I);    Ar1 and Ar2=aryl or heteroaryl that is different from U', preferably has 5 to 30 ring atoms and is optionally substituted by R's;    R's=F, Br, Cl, -CN, -NC, -NCO, -NCS, -OCN, -SCN, -C(O)NR'nR'n1, -C(O)X', -C(O)R'n, -NH2, -NR'nR'n1, -SH, -SR'n, -SO3H, -SO2R'n, -OH, -NO2, -CF3, -SF5, optionally substituted silyl, 1-40C carbyl or hydrocarbyl that is optionally substituted and optionally comprises hetero atoms;    R'n and R'n1=H or optionally substituted 1-40C carbyl or hydrocarbyl;    X'=halo, preferably F, Cl or Br;    R7 and R8=Cl, Br, I, O-tosylate, O-triflate, O-mesylate, O-nonaflate, -SiMe2F, -SiMeF2, -O-SO2Z1, -B(OZ2)2 , -CZ3=C(Z3)2, -C?=CH, -C?=CSi(Z1)3, -ZnX' or -Sn(Z4)3;    Z1-Z4=alkyl and aryl, each being optionally substituted.    Two groups Z2 may also together form a cyclic group.