5-Substituted 7H-1,2,3-triazolo [4,5-d]pyrimidin-7-ones (4) were rapidly prepared by a solution-phase parallel synthetic method, which includes aza-Wittig reaction of iminophosphorane (1) with phenyl isocynate to give carbodiimide (2) and subsequent reaction of 2 with various amine and alcohols in the presence of catalytic amount of sodium alkoxide in a parallel fashion.