Chemoselective polycondensation of 2-amino-4,6-dichloro-1,3,5-triazine (ADCT) was investigated with various aromatic diamines such as 4,4'-oxydianiline (ODA), 9,9-bis(4-aminophenyl)fluorene (BAFL), 4,4'-(hexafluoropropane-2,2-diyl)dianiline (BisAF), and bis(4-aminophenyl)sulfone (SODA) in the presence of potassium carbonate as a base. High-molecular weight perfectly linear polyguanamines (M-n approximate to 46000) were successfully obtained for the polycondensation of ADCT with BisAF, while the polycondensation of ADCT with BAFL afforded branched polyguanamines with a degree of branching of from 0.02 to 0.17.