Hyperbranched conjugated polymers (P1, P2 and P3) containing different aryl groups appended with carboxylic ester groups were synthesized by metal-free catalyzed polymerization via A₂ + B₃ type monomers. These as-prepared polymers can be dissolved well in common organic solvents and have good thermal stability. These polymers were investigated as fluorescence chemosensor for the detection of biologically important metal ion Fe³⁺. The corresponding Stern-Volmer constants (K_sv) of P1, P2 and P3 were 3.99 × 10⁴ M⁻¹, 5.15 × 10⁴ M⁻¹ and 3.99 × 10⁴ M⁻¹, respectively. The detection limits of 1.203 × 10⁻⁷ M for P1, 8.487 × 10⁻⁷ M for P2 and 7.158 × 10⁻⁶ M for P3 were achieved. In addition, the water-soluble hyperbranched conjugated polymers were obtained by hydrolysis of neutral polymer P1, P2 and P3. The ability of water-soluble polymers to detect Fe³⁺ ion in an aqueous solution was investigated in this work. The results demonstrated that the different aryl moieties in backbone of hyperbranched polymers mainly affected their energy band instead of their selective detection of Fe³⁺ ions. All the polymers were highly sensitive and selective toward Fe³⁺ ions in organic solvents and aqueous solution, indicating that these polymers could be used as fluorescence chemosensor for Fe³⁺ ions in real time.