A compound of the formula wherein m is 0 or 1; wherein at least one, or both R 1 and R 2 is independently CN; NO 2; an optionally substituted aryl; an optionally substituted heteroaryl; an optionally substituted alkenyl; an optionally substituted alkynyl; COR 3 or SOR 3 or SO 2 R 3 wherein R 3 is H or an optionally substituted alkyl; aryl or arylalkyl, each optionally substituted; heteroaryl or heteroarylalkyl, each optionally substituted; or OR 9 or NR 9 2 wherein each R 9 is independently H or an optionally substituted alkyl, or both R 9 groups taken together with the nitrogen to which they are attached form a heterocyclic ring; wherein R 1 and R 2 may be joined to form a 3-8 membered ring; and wherein one and only one of R 1 and R 2 may be H or alkyl, arylalkyl or heteroarylalkyl, each optionally substituted; each R 5 is independently H or is alkyl, alkenylalkyl, alkynylalkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl, each optionally substituted; Z is a residue of a drug or prodrug coupled through O, S, or non-basic N or is a nucleofuge that mediates said coupling; B is alkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl, each optionally substituted; and wherein one of R 1, R 2, R 5 and B is coupled to a macromolecule or one of R 1, R 2 and R 5 comprises a functional group for mediating said coupling; wherein the substituents for any optionally substituted group defined above are selected from halo, nitro, cyano, OR, SR, NR 2, OCOR, NRCOR, COOR, CONR 2, SOR, SO 2 R, SONR 2, SO 2 NR 2, wherein each R is independently alkyl, alkenyl, alkynyl, aryl or heteroaryl, or two R groups taken together with the atoms to which they are attached form a ring; and wherein the substitution on any ring system may also be selected from alkyl, alkenyl, alkynyl, or an additional ring, each of which may be optionally substituted. wherein at least one, or both R 1 and R 2 is independently CN; NO 2; an optionally substituted aryl; an optionally substituted heteroaryl; an optionally substituted alkenyl; an optionally substituted alkynyl; COR 3 or SOR 3 or SO 2 R 3 wherein R 3 is H or an optionally substituted alkyl; aryl or arylalkyl, each optionally substituted; heteroaryl or heteroarylalkyl, each optionally substituted; or OR 9 or NR 9 2 wherein each R 9 is independently H or an optionally substituted alkyl, or both R 9 groups taken together with the nitrogen to which they are attached form a heterocyclic ring; an optionally substituted aryl; an optionally substituted heteroaryl; an optionally substituted alkenyl; an optionally substituted alkynyl; COR 3 or SOR 3 or SO 2 R 3 wherein R 3 is H or an optionally substituted alkyl; aryl or arylalkyl, each optionally substituted; heteroaryl or heteroarylalkyl, each optionally substituted; or OR 9 or NR 9 2 wherein each R 9 is independently H or an optionally substituted alkyl, or both R 9 groups taken together with the nitrogen to R 3 is H or an optionally substituted alkyl; aryl or arylalkyl, each optionally substituted; heteroaryl or heteroarylalkyl, each optionally substituted; or OR 9 or NR 9 2 wherein each R 9 is independently H or an optionally substituted alkyl, or both R 9 groups taken together with the nitrogen to which they are attached form a heterocyclic ring; wherein R 1 and R 2 may be joined to form a 3-8 membered ring; and wherein one and only one of R 1 and R 2 may be H or alkyl, arylalkyl or heteroarylalkyl, each optionally substituted; each R 5 is independently H or is alkyl, alkenylalkyl, alkynylalkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl, each optionally substituted; Z is a residue of a drug or prodrug coupled through O, S, or non-basic N or is a nucleofuge that mediates said coupling; B is alkyl, aryl, arylalkyl, heteroaryl or heteroarylalkyl, each optionally substituted; and wherein one of R 1, R 2, R 5 and B is coupled to a macromolecule or one of R 1, R 2 and R 5 comprises a functional group for mediating said coupling; wherein the substituents for any optionally substituted group defined above are selected from halo, nitro, cyano, OR, SR, NR 2, OCOR, NRCOR, COOR, CONR 2, SOR, SO 2 R, SONR 2, SO 2 NR 2, wherein each R is independently alkyl, alkenyl, alkynyl, aryl or heteroaryl, or two R groups taken together with the atoms to which they are attached form a ring; and wherein the substitution on any ring system may also be selected from alkyl, alkenyl, alkynyl, or an additional ring, each of which may be optionally substituted.