Protein kinases phosphorylate client proteins, while protein phosphatases catalyze their dephosphorylation and thereby in concert exert reversible control over numerous signal transduction pathways. We have recently reported the design and validation of split-protein kinases that can be conditionally activated by an added small molecule chemical inducer of dimerization (CID), rapamycin. Herein, we provide the rational design and validation of three split-tyrosine phosphatases (PTPs) attached to FKBP and FRB, where catalytic activity can be modulated with rapamycin. We further demonstrate that the orthogonal CIDs, abscisic acid and gibberellic acid, can be used to impart control over the activity of split-tyrosine kinases (PTKs). Finally, we demonstrate that designed split-phosphatases and split-kinases can be activated by orthogonal CIDs in mammalian cells. In sum, we provide a methodology that allows for post-translational orthogonal small molecule control over the activity of user defined split-PTKs and split-PTPs. This methodology has the long-term potential for both interrogating and redesigning phosphorylation dependent signaling pathways.