The present invention relates to novel methods and novel solid support materials for the tandem synthesis of two or more different oligonucleotides on the same solid support in one synthetic run. The methods involve novel support preparations comprised of two or more types of orthogonally protected anchor groups. Subsequent to the selective removal of the first of the respective protective groups, the first oligonucleotide is assembled on the deblocked anchor groups according to standard methods, preferably via phosphoramidite chemistry. Following the capping of said first oligonucleotide, the anchor groups blocked by a second type of protective group are selectively liberated and serve as the starting point for the assembly of a second oligonucleotide, and so forth. After completion of all the syntheses on the solid support, the oligonucleotides are released from the solid support and deprotected at the nucleobases, using standard methods. Preparations obtained using the method of this invention, generally contain two or more different oligonucleotides. Such preparations are particularly useful in applications that require pairs of oligonucleotide primers, several probes at a time, duplexed nucleic acid fragments, or other combinations of oligonucleotides that are useful in applications such as PCR, sequencing, multiplexed genotyping, cloning and RNA interference. The invention includes procedures for the preparation of the novel solid supports of the invention.