A compound of Formula comprising block repeat block monomer units (a) and/or (b) and/or (c) and/or (d): L 1 is a linking group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, and any combination thereof; L 2 is absent, or can be of the formula: L 2A is a linking group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, -C -, -NR c -, and any combination thereof; L 2B and L 2C are independently absent or a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene,, -C -, -NR c -, and any combination thereof; B 2A and B 2B are independently absent or a cleavable linker; T is a therapeutic agent selected from the group consisting of chemotherapeutic agents, microtubule inhibitors, DNA-damaging agents and RNA transcription inhibitors; L 3 is a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, and any combination thereof; R e is a substituent selected from hydrogen, alkyl and heteroalkyl; L 4 is a group of the formula: L 4A is a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, -C -, -NR c -, and any combination thereof; L 4B and L 4C are independently absent or a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, -C -, -NR c -, and any combination thereof; B 4A and B 4B are independently absent or a cleavable linker; C 4A is a group selected from and where A is -H or a targeting moiety selected from the group consisting of an antibody, a synthetically functionalized antibody, a peptide and a targeting ligand; "n" is independently at each occurrence an integer ranging from 0-5; R c and R d are independently selected at each occurrence from hydrogen, alkyl, heteroalkyl, cycloalkyl, and heterocyclyl; each cleavable linker B 2A, B 2B, B 4A and B 4B, if present, is independently selected from -S-S-, -C(=O)O-, -OC(=O)-, -C(=O)NR c -, -N(R c)C(=O)-, -OC(=O)O-, -NR c C(=O)O-,-OC(=O)N(R c)- or -N(R c)C(=O)N(R d)-, -C(=O)N(R c)C(=O)-, -C(=O)S-, -SC(=O)-,-SC(=O)S-, -OC(=O)S-, -SC(=O)O-, -OC(=S)O-, -SC(=S)S-, -N(R c)SO 2 -, -SO 2 N(R c)-, -N(R c)SO 2 N(R d)-, -C(=O)N(R c)N(R d)-, -N(R c)N(R d)C(=O)-, -N(R c)N(R d)C(=O)O-,-OC(=O)N(R c)N(R d)-, -C(R c)=N-NH-C(=O)-, -C(=O)NH-N=C(R c)-, -C(R c)=N-O-,-O-N=C(R c)-, where each monomer is substituted independently from any additional monomer; with the proviso that the compound of Formula contains one or more therapeutic agents, T, and one or more targeting moieties A. L 1 is a linking group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, and any combination thereof; L 2 is absent, or can be of the formula: L 2A is a linking group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, -C -, -NR c -, and any combination thereof; L 2B and L 2C are independently absent or a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene,, -C -, -NR c -, and any combination thereof; B 2A and B 2B are independently absent or a cleavable linker; T is a therapeutic agent selected from the group consisting of chemotherapeutic agents, microtubule inhibitors, DNA-damaging agents and RNA transcription inhibitors; L 3 is a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, and any combination thereof; R e is a substituent selected from hydrogen, alkyl and heteroalkyl; L 4 is a group of the formula: L 4A is a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, -C -, -NR c -, and any combination thereof; L 4B and L 4C are independently absent or a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, -C -, -NR c -, and any combination thereof; B 4A and B 4B are independently absent or a cleavable linker; C 4A is a group selected from and where A is -H or a targeting moiety selected from the group consisting of an antibody, a synthetically functionalized antibody, a peptide and a targeting ligand; "n" is independently at each occurrence an integer ranging from 0-5; R c and R d are independently selected at each occurrence from hydrogen, alkyl, heteroalkyl, cycloalkyl, and heterocyclyl; each cleavable linker B 2A, B 2B, B 4A and B 4B, if present, is independently selected from -S-S-, -C(=O)O-, -OC(=O)-, -C(=O)NR c -, -N(R c)C(=O)-, -OC(=O)O-, -NR c C(=O)O-,-OC(=O)N(R c)- or -N(R c)C(=O)N(R d)-, -C(=O)N(R c)C(=O)-, -C(=O)S-, -SC(=O)-,-SC(=O)S-, -OC(=O)S-, -SC(=O)O-, -OC(=S)O-, -SC(=S)S-, -N(R c)SO 2 -, -SO 2 N(R c)-, -N(R c)SO 2 N(R d)-, -C(=O)N(R c)N(R d)-, -N(R c)N(R d)C(=O)-, -N(R c)N(R d)C(=O)O-,-OC(=O)N(R c)N(R d)-, -C(R c)=N-NH-C(=O)-, -C(=O)NH-N=C(R c)-, -C(R c)=N-O-,-O-N=C(R c)-, where each monomer is substituted independently from any additional monomer; with the proviso that the compound of Formula contains one or more therapeutic agents, T, and one or more targeting moieties A.