Inventors have developed a chromophore (nitrodibenzylfuranyl, or NBDF) for ultra efficient uncaging of a caged substrate (e.g., an organic molecule such as, for example, an amino acid, a biological molecules, such as, for example, second messengers inside cells). Photolysis of a NBDF derivative of EGTA (i.e. caged calcium) is about 50 times more efficient than others calcium cages (the quantum yield of photolysis is 0.6 and the extinction coefficient is 18,400. NDBF-EGTA has a 2-photon cross section of about 0.3-0.6 GM).