N Mix CPG (5'-DMT-[dA(Bz), dC(Ac), dG(iBu), T]-Suc-CPG); 1000 Å is a reagent used in the solid-phase synthesis of oligonucleotides to incorporate a randomized mixture of the four nucleosides: deoxyadenosine (dA) with benzoyl (Bz) protection, deoxycytidine (dC) with acetyl (Ac) protection, deoxyguanosine (dG) with isobutyryl (iBu) protection, and thymidine (T). These nucleosides are linked via a succinyl (Suc) linker to controlled pore glass (CPG) with a 1000 Å pore size. The reagent is designed for synthesizing randomized oligonucleotide sequences, enabling the creation of diverse sequence libraries. The 5'-DMT group protects the 5' end during synthesis, ensuring controlled and efficient oligonucleotide assembly.