We are interested in the reaction chemistry of small molecules that are too reactive to be stored in a bottle. In order to access their chemistry, we design and synthesize molecular precursors that can be activated by a stimulus to release a small molecule of interest. The molecular precursors themselves are isolated as crystalline solids, they are typically soluble in common organic solvents, and they can be weighed out and used as needed. For example, the molecule P2A2 (A = anthracene or C14H10) is a molecular precursor to the reactive diatomic molecule P2. Heating a solution containing P2A2 in the presence of a P2 acceptor (examples include organic 1,3-diene molecules, the azide ion) results in loss of 2 A and transfer of the P2 unit to the acceptor. We also show that heating a solid sample of P2A2 leads to evolution of P2 into the gas phase. In choosing our targets we take inspiration from interstellar chemistry; other reactive intermediates to be discussed include HCP and R2N-P, aminophosphinidenes. Our efforts to generate HPS resulted in serendipitous access to a new P2S solid-state material of interest for its electronic properties. Finally, the chemistry of PN as a complex ligand with singlet phosphinidene reactivity will be discussed.