Although 2,2,4,4-tetramethyl-1,3-cyclobutadione (TMCBDI) has been known for more than 50 years, it has never been used for synthesis of polymer primarily due to its inefficiency in direct polycondensation reaction. We report the first synthesis of high molecular weight polyimines prepared from TMCBDI using Pd-catalyzed Suzuki coupling polymerization. To overcome sluggish condensation polymerization of TMCBDI, it was first converted to diimine monomer containing phenyl bromide on both sides (compound 1) via condensation reaction and polymerized with three different examples aryl diboronate compounds (2a, 2b, 2c). The resulting polyimines (3a, 3b, 3c) were found to exist in a mixture of E and Z isomers in a ratio of 2:1. The number and weight average molecular weights of polyimines were high considering the rigidity of the backbone structure: 20,000 and 44,300 g/mol and 23,100 and 40,500 g/mol for 3a and 3b, respectively. They also showed good thermal stability over 340 °C and a high glass transition temperature over 220 °C. There was no observable photoluminescence from the polyimines in the range of 800 to 300 nm. Apparently, the TMCBDI moiety disrupts electron delocalization in conjugated backbone of polymer chains.