New mono- and disubstituted pyrido[3,2-d]pyrimidines have been synthetized starting from 2,3-pyridinedicarboxilic anhydride. After obtaining the key intermediate 2,4-dichloropyrido[3,2-d]pyrimidine, many regioselective reactions, showed that dechlorination and SNAr have been realized in position 4. Subsequently, the residual chlorine atom in position 2 has been involved in a series of palladium-catalyzed couplings of Suzuki type.