A crystal engineering approach has been adopted to generate a combinatorial library of 40 primary ammonium monocarboxylate salts derived from 10 cinnamic acid derivatives and 4 n-alkyl primary amines, as potential organic gelators. It is observed that 4-Cl, 4-Me, and 4-Br cinnamate salts of CH3(CH2)(n)NH2 (n = 15) are gelators. A systematic study of 4-Br cinnamate salts of n-alkylamine with varying chain lengths indicates that the alkyl chain length has a profound effect on gelation. A structure-property correlation study has been attempted on the basis of single-crystal and powder X-ray diffraction data of the salts.