The present invention relates to photolabile or photoreleasable compounds including a caging moiety linked to an effector moiety, wherein the compounds are capable of releasing the effector moiety on irradiation, typically by flash irradiation with UV light. These compounds are particularly suitable for focal 2-photon uncaging The photoreleasable compounds can be used to deliver effector moieties such as carboxylic acids, preferably, neuroactive amino acids to sites where their activity is required. In preferred embodiments of the invention, the caging moiety is based on 4-carboxymethoxy-5,7-dinitroinlinyl and derivatives thereof.