Sequence-controlled semiconducting polymers represent a new frontier in organic electronics, where precise molecular sequence directly dictates device performance. However, achieving both high sequence fidelity and structural diversity remains a significant challenge using conventional synthetic protocols. To address this issue, we introduce a versatile halide-pair-driven multicomponent polymerization (MCP) strategy that enables the library synthesis of sequence-controlled semiconducting poly(triarylamine)s (PTAAs). By optimizing halide pairing in conjunction with a rationally designed Buchwald ligand-Pd system featuring catalyst-transfer capability, we achieved efficient sequential cascade aminations, thereby enabling the MCP. The versatility of this strategy was demonstrated through the synthesis of a library of sequence-controlled PTAAs, including dendronized variants, underscoring its potential as a general platform for functional semiconducting material discovery.