Abstract: A carbazole of formula I wherein R1 and R2 are each independently halo, B(OH)2, B(OR7)2, Sn(R6), C1-20 hydrocarbyl, or C1-20 hydrocarbyl comprising one or more hetero atoms, R3 is H, halo, C1-20 hydrocarbyl, C1-20 hydrocarbyl comprising one or more heteroatoms, or cyano, R4 and R5 are each independently H, halo, C1-20 hydrocarbyl, Cl-20 hydrocarbyl comprising one or more heteroatoms, or cyano, and R7 and R8 are each independently C1-20 hydrocarbyl, provided that R4 and R5 are not both H when R3 is n-octyl, and conjugated oligomers, polymers and co-polymers thereof. Embodiments of the oligomers, polymers and co-polymers can, for example, be formed into films which can be incorporated into electronic devices.