Photographic element containing a coupler capable of releasing a photographically useful group

A photographic element comprising a support having situated thereon at least one silver halide emulsion layer, the layer containing a photographic coupler represented by the formula ##STR20## wherein COUP is a coupler moiety having a coupling site to which T.sup.1 is attached;

• T.sup.1 is a timing or linking group which releases from COUP during processing and which functions by electron transfer down a conjugated chain, or by nucleophilic displacement reaction, to release from HETERO;
• HETERO is selected from a pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, tetrazole, indazole, benzimidazole, benzotriazole, pyrazolotriazole, pyrazoloimidazole or triazoloimidazole group, wherein one of the heteroatoms is directly attached to T.sup.1 ;
• R.sup.1 and R.sup.2 are independently selected from hydrogen, or an aliphatic, carbocyclic, or heterocyclic group, or may be bonded together to form a 5, 6, or 7 membered ring;
• and
• PUG is a photographically useful group.