The 1:1 adduct of 4-aminobenzoic acid (PABA) with 4-am-inobenzonitrile (PABN), C(7)H(7)NO(2).C(7)H(6)N(2), consists of a primary centrosymmetric cyclic hydrogen-bonded PABA dimer interaction [O.O 2.640 (3) A] peripherally linked into chains by weaker hydrogen bonds via a head-to-tail PABN interaction [N.N 3.179 (4) and N.O 3.062 (4) A], and is linked between the chains by amine-N (PABN) to amine-N (PABA) interactions [N.N 3.233 (5) A]. No proton transfer occurs.