A compound having a chemical structure according to Formula I, or a stereoisomer or pharmaceutically acceptable salt thereof: wherein A is wherein each "*" designates an attachment point of A; the bonds represented by " " are single or double bonds as needed to satisfy valence requirements; R 1 -R 9 and R 11 independently are H, sulfonate, -N(R a) 2, deuterium, unsubstituted branched, unbranched, or cyclic alkyl, unsubstituted heteroalkyl, unsubstituted alkyl sulfonate, unsubstituted aminoalkyl, -C OR a, trityl, or a group comprising a conjugatable moiety, a targeting agent, or a drug, where each R a independently is H, deuterium, unsubstituted alkyl, or unsubstituted heteroalkyl; R 10 is H, deuterium, O, unsubstituted branched, unbranched, or cyclic alkyl, unsubstituted aryl, unsubstituted amino, sulfonate, triflate, -C OR b, -OR b, -N(R b) 2, unsubstituted heteroalkyl, unsubstituted heteroaryl, unsubstituted trityl, or a group comprising a conjugatable moiety, a targeting agent, or a drug, where each R b independently is H, deuterium, unsubstituted branched, unbranched, or cyclic alkyl, unsubstituted heteroalkyl, unsubstituted aryl, or unsubstituted heteroaryl; and Y 1 and Y 2 independently are C(R c) 2, N(R d), S, O, or Se, wherein each R c independently is unsubstituted branched, unbranched, or cyclic alkyl, H, deuterium, -(OCH 2 CH 2) x OH where x is an integer ≥ 2, trityl, or a group comprising a conjugatable moiety, a targeting agent, or a drug, and each R d independently is H, deuterium, unsubstituted branched, unbranched, or cyclic alkyl, or usubstituted heteroalkyl; wherein the conjugatable moiety is selected from or where y is an integer ≥ 1, or a phosphoramidite group; wherein the targeting agent is selected from proteins, polypeptides, peptides, glycoproteins and other glycoslyated molecules, oligonucleotides, phospholipids, lipoproteins, alkaloids, steroids, antibodies, antibody fragments, affibodies, aptamers, albumin, cytokines, lymphokines, growth factors, hormones, enzymes, immune modulators, receptor proteins, antisense oligonucleotides, avidin, nano particles, nucleic acid sequences, and receptor ligands; wherein the drug has a molecular weight <1000 Daltons. wherein A is wherein each "*" designates an attachment point of A; the bonds represented by " " are single or double bonds as needed to satisfy valence requirements; R 1 -R 9 and R 11 independently are H, sulfonate, -N(R a) 2, deuterium, unsubstituted branched, unbranched, or cyclic alkyl, unsubstituted heteroalkyl, unsubstituted alkyl sulfonate, unsubstituted aminoalkyl, -C OR a, trityl, or a group comprising a conjugatable moiety, a targeting agent, or a drug, where each R a independently is H, deuterium, unsubstituted alkyl, or unsubstituted heteroalkyl; R 10 is H, deuterium, O, unsubstituted branched, unbranched, or cyclic alkyl, unsubstituted aryl, unsubstituted amino, sulfonate, triflate, -C OR b, -OR b, -N(R b) 2, unsubstituted heteroalkyl, unsubstituted heteroaryl, unsubstituted trityl, or a group comprising a conjugatable moiety, a targeting agent, or a drug, where each R b independently is H, deuterium, unsubstituted branched, unbranched, or cyclic alkyl, unsubstituted heteroalkyl, unsubstituted aryl, or unsubstituted heteroaryl; and Y 1 and Y 2 independently are C(R c) 2, N(R d), S, O, or Se, wherein each R c independently is unsubstituted branched, unbranched, or cyclic alkyl, H, deuterium, -(OCH 2 CH 2) x OH where x is an integer ≥ 2, trityl, or a group comprising a conjugatable moiety, a targeting agent, or a drug, and each R d independently is H, deuterium, unsubstituted branched, unbranched, or cyclic alkyl, or usubstituted heteroalkyl; wherein the conjugatable moiety is selected from or where y is an integer ≥ 1, or a phosphoramidite group; wherein the targeting agent is selected from proteins, polypeptides, peptides, glycoproteins and other glycoslyated molecules, oligonucleotides, phospholipids, lipoproteins, alkaloids, steroids, antibodies, antibody fragments, affibodies, aptamers, albumin, cytokines, lymphokines, growth factors, hormones, enzymes, immune modulators, receptor proteins, antisense oligonucleotides, avidin, nano particles, nucleic acid sequences, and receptor ligands; wherein the drug has a molecular weight <1000 Daltons.