The present invention provides methods of synthesizing libraries of molecules comprising a functional moiety which is operatively linked to an encoding oligonucleotide. The methods generally include providing a solution comprising initiator compounds comprising an initial functional moiety which comprises n building blocks which comprise at least one reactive group, which is operatively linked to an initial oligonucleotide; dividing the solution into reaction vessels; reacting the initiator compounds in each reaction vessel with a building block comprising a complementary reactive group to form a covalent bond; and reacting the initial oligonucleotide in each aliquot with a distinct incoming oligonucleotide in the presence of an enzyme which catalyzes the ligation of the incoming oligonucleotide and the initial oligonucleotide, under conditions suitable for enzymatic ligation of the incoming oligonucleotide and the initial oligonucleotide to form an encoding oligonucleotide which identifies the structure of the functional moiety.