Dicyanamide (abbreviated as dca when a ligand) is an anion with the formula C₂N−3. It contains two cyanide groups bound to a central nitrogen anion. Dicyanamide is formed by decomposition of 2-cyanoguanidine.^{[citation needed]}

Dicyanamide is used extensively as a counterion of organic and inorganic salts, as it is a "chemically inert, hydrophobic anion" and pseudohalide. It is also as a reactant for the synthesis of various covalent organic structures.

Dicyanamide has a very low proton affinity, less than 310 ± 3 kcal·mol⁻¹. Its gas-phase conjugate acid is iminomethylidenecyanamide [wd] HN=C=N−C≡N, which is predicted to be slightly more stable than the symmetric tautomer dicyanimide [wd] N≡C−NH−C≡N.

Dicyanamide was used as an anionic component in an organic superconductor that was, when reported in 1990, a superconductor with the highest transition temperature in its structural class.

Dean Kenyon examined the role of this chemical in reactions that can produce peptides, and a co-worker examined dicyanamide's possible role in primordial biogenesis.