TECHNOLOGY FOCUS - ELECTRONICS - Preferred Device: In the organic electronic device, the semiconducting layer is an organic light-emitting layer. The light-emitting layer comprises a fluorescent blue light-emitting material, phosphorescent light-emitting material or green phosphorescent light-emitting material. In the organic electronic device, a light-emitting layer or hole-transporting layer of the device comprises the polymer (C1). In the organic electronic device, light-emitting layer of the device comprises the polymer (C1) and a phosphorescent dopant blended with or bound to the polymer. Preferred Method: In the method (M1), the hole transporting layer is formed by depositing a formulation comprising the polymer comprising repeat units (I) and at least one solvent and evaporating the solvents, where the hole-transporting layer is crosslinked prior to formation of the semiconducting layer.    TECHNOLOGY FOCUS - POLYMERS - Preparation (Claimed): Forming a polymer (C1) involves polymerizing the monomer (VIIm) in the presence of a metal catalyst. In the method, the monomer is polymerized in the presence of at least one co-monomer to form a copolymer. Preferred Components: The polymer comprises at least two different co-repeat units. At least one co-repeat unit is an aromatic group that may be optionally substituted with at least one substituent. The co-repeat unit is a repeat unit of formula (III) or (IV). The copolymer is crosslinked. The polymer comprises crosslinking substituent. The co-polymer is crosslinked through a crosslinking substituent of a repeat unit of the polymer. The repeating unit (VII) is a compound of formula (VIIa).p=0-4, optionally 1 or 2;n=1-3;R1 and R8=substituent;R3=H or substituent;d=0-3.The two groups R3 may be linked to form a ring. Preferred Definitions:    R=aryl or heteroaryl group that may be optionally substituted with at least one substituent;    R6=hydrocarbyl, preferably 1-40C hydrocarbyl;    LG'=halo, boronic acid, boronic acid esters, sulfonic acid or sulfonic acid esters.    Each Ar1 comprises at least six sp2 hybridized atoms, optionally at least eight sp2 hybridized atoms, spacing the N atom bound to each Ar1 from an adjacent repeat unit.