<p>Nickel-based superalloys, represented by GH4169, are extensively used in the aerospace industry due to their excellent high-temperature strength and corrosion resistance. However, the formation of excessive brittle intermetallic compounds during wide gap brazing often compromises joint integrity. In this study, two novel boron-and silicon-free High-entropy alloy fillers, Co₂₀Ni₂₀Fe₅Mn₃₀Cu₂₀Al₅ and Co₂₀Ni₂₀Fe₅Mn₃₀Cu₂₀Al₂Ti₃, were developed to improve the strength and toughness of brazed GH4169 joints. The interfacial microstructure evolution, brazing mechanisms, and mechanical properties of the joints brazed at 1200 °C with different holding times were systematically investigated. The results revealed that in the athermal solidification zone (ASZ), the Co₂₀Ni₂₀Fe₅Mn₃₀Cu₂₀Al₅ filler exhibited intergranular segregation, which was accompanied by the formation of Cu-rich phases. In contrast, the addition of Ti in Co₂₀Ni₂₀Fe₅Mn₃₀Cu₂₀Al₂Ti₃ was associated with the formation of Ti–rich segregated phases and in-situ TiC phases. The presence of TiC phases appeared to restrict grain boundary migration, which corresponded to significant grain refinement within the brazed seam. The Co₂₀Ni₂₀Fe₅Mn₃₀Cu₂₀Al₂Ti₃ brazed joint exhibits enhanced high-temperature tensile strength and a refined microstructure. Its average room-temperature tensile strength reaches 765.7 MPa, and its high-temperature tensile strength at 850 °C remains as high as 259.08 MPa.</p>