In this paper, a highly chemical stable 4,4′,4″-((1,3,5-triazine-2,4,6-triyl)tris(oxy))trianiline (TTA) was successfully synthesized with 4,4′-(4,4′-Isopropylidene-diphenoxy)bis(phthalic anhydride) (BPADA) using direct nucleophilic addition in Dimethylformamide (DMF). The resulting Hyperbranched Polyimide (HPI) was characterized by means of conventional methods such as Fourier transform infra-red (FT-IR) and proton nuclear magnetic resonance (¹H NMR) spectroscopy, gel permeation chromatography (GPC), solubility tests, Field Emission Scanning Electron Microscopy (FESEM), Electron Diffraction X-ray analysis (EDX), Vickers hardness test, thermogravimetric analysis (TG), differential scanning calorimetry (DSC), and thermal conductivity. High molecular weight was obtained by extending the reaction time for 2 h. The TTA/BPADA HPI demonstrated a high chemical stability and could be readily used in the precursor state. The thermal curing led to an increase of the imidization degree and greatly improved the thermal stability (Tg above 200 °C, maximum mass loss >500 °C and char yield >55%), due to an increasing chain packing density). Therefore, it is believed that this incorporated HPI structure containing s-triazine moieties in a polyimide system shows potential as a new high performance and highly functional material.