The flow of genetic information can be affected at various stages, ultimately leading to the up- or down-regulation of gene expression. Essential to elucidating gene function is first gaining precise external control over biological processes. Many techniques currently employed to investigate gene function may interfere with normal downstream processes or harm the organism of study, and their applications often lack specificity. Photochemical biology provides an alternative approach, in which a light-removable protecting group (termed “caging group”) installed on a protein or nucleic acid inhibits its nascent function; non-damaging light irradiation removes the caging group and restores activity. Additionally, light-responsive moieties such as diazobenzenes can be harnessed as reversible photoregulated groups for controlling biological macromolecules. Since light-irradiation can be precisely regulated, decaging can be achieved with a high level of spatial and temporal control. The research described herein reports the development of novel tools to achieve spatio-temporal control of biological processes through the photoregulation of proteins and nucleic acids, both in vitro and in vivo . Specifically, our approaches involve (1) modulating enzymatic activity by directly installing a caging group on the protein of interest, (2) utilizing photocaged nucleotides to regulate the polymerase chain reaction, (3) investigating the effects of microwave irradiation on nucleic acids, and (4) controlling protein dimerization through the use of a photoregulated chemical inducer of dimerization (CID).