Conjugated polymers

A monomer of formula V

• R2—Ar1—U—Ar2—R3 V
• wherein
• U is a unit of formula I or a unit of formula Ia-Id,
• R2 and R3 are each, independently of each other, F, Br, Cl, —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, optionally substituted silyl, carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, or P-Sp-, preferably F, Br or Cl, or denote H, —CH2Cl, —CHO, —CH═CH2, —SiR′R″R′″, —SnR′R″R″, —BR′R″, —B(OR′)(OR″), —B(OH)2 or P-Sp, wherein P and Sp are as defined above, and R′, R″ and R′″ are each, independently of each other, H or optionally substituted C1-40 carbyl or hydrocarbyl, and two of R′, R″ and R′″ may also form a ring together with the hetero atom to which they are attached, and
• Ar1, Ar2 are are, on each occurrence identically or differently, and independently of each other, aryl or heteroaryl, preferably having 5 to 30 ring atoms, which is optionally substituted, preferably by one or more groups R1, and
• R1 is on each occurrence identically or differently F, Br, Cl, —CN, —NC, —NCO, —NCS, —OCN, —SCN, —C(O)NR0R00, —C(O)X°, —C(O)R0, —NH2, —NR0R00, —SH, —SR0, —SO3H, —SO2R0, —OH, —NO2—CF3, —SF5, optionally substituted silyl, carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, or P-Sp-.