NOVELTY - Indacenodithiophene or indacenoselenophene monomeric unit (I) is new. s    USE - As charge transport, semi-conducting, electrically conducting, photo-conducting or light emitting material in optical, electrooptical, electronic, electroluminescent or photo-luminescent components or devices selected from organic field effect transistors (OFET), thin film transistors (TFT), integrated circuits (IC), logic circuits, capacitors, radio frequency identification (RFID) tags, devices or components, organic light emitting diodes (OLED), organic light emitting transistors (OLET), flat panel displays, backlights of displays, organic photovoltaic devices (OPV), solar cells, laser diodes, photoconductors, photo-detectors, electrophotographic devices, electrophotographic recording devices, organic memory devices, sensor devices, charge injection layers, charge transport layers or interlayers in polymer light emitting diodes (PLEDs), Schottky diodes, planarizing layers, antistatic films, polymer electrolyte membranes (PEM), conducting substrates, conducting patterns, electrode materials in batteries, alignment layers, biosensors, biochips, security markings, security devices, bulk heterojunction OPV device, and components or devices for detecting and discriminating DNA sequences (claimed).    ADVANTAGE - The monomer (I) comprising the conjugated polymer have good processibility and at the same time show high charge carrier mobility and high oxidative stability.    DETAILED DESCRIPTION - Indacenodithiophene or indacenoselenophene monomeric unit of formula (I) is new.    A1 and A2=single bond or CR1R2;    A3 and A4=single bond or CR3R4;    U1-U4=-CH=, =CH- or -X-;    X=-S- or -Se-;    R1-R4=H, halo, -CN, -NC, -NCO, -NCS, -OCN, -SCN, -C(O)NR1aR1b, -C(O)X0, -C(O)R1a, -NH2, -NR1aR1b, -SH, -SR1a, -SO3H, -SO2R1a, -OH, -NO2, -CF3, -SF5, P1-Sp-, optionally substituted silyl, or carbyl or hydrocarbyl (having 1-40 carbon atoms; and both optionally substituted and optionally comprises at least one heteroatom);    P1=polymerizable group;    Sp=spacer group or single bond;    X0=halo;    R1a and R1b=H, or carbyl or hydrocarbyl group (both optionally substituted and optionally comprising at least one heteroatom);    Ar1 and Ar2=optionally substituted (hetero)aryl, -CY1=CY2- or -C?=C-;    Y1 and Y2=H, F, Cl or CN;    m1 and m2=0-4;    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 or -Sn(Z3)3;    Z1-Z4=alkyl or aryl (both optionally substituted);    Z1+Z1=cyclic group.    Provided that:    (A) one of A1 and A2 is a single bond and other is CR1R2;    (B) one of A3 and A4 is single bond and other is CR3R4;    (C) one of U1 and U2 is -CH= or =CH- and other is -X-;    (D) one of U3 and U4 is -CH= or =CH- and other is -X-; and    (E) if A1-A4 is single bond, then U1-U4 is X respectively.    INDEPENDENT CLAIMS are included for the following:    (1) new conjugated polymer comprising at least one indacenodithiophene or indacenoselenophene monomeric unit of formula (I);    (2) polymer blend comprising the at least one conjugated polymer and at least one polymer, preferably selected from polymers having semi-conducting, charge transport, hole/electron transport, hole/electron blocking, electrically conducting, photo-conducting or light emitting properties;    (3) formulation comprising the at least one conjugated polymer or its blend and at least one solvent, preferably selected from organic solvents; and    (4) preparation of the conjugated polymer involving subjecting the at least one monomer (II), and optionally at least one monomer of formula R7-Ar1-R8 and/or R7-Ar2-R8, to an aryl-aryl coupling reaction.