Mid-infrared photodissociation spectra of mass selected C3H3+-N-2 ionic complexes are obtained in the vicinity of the C-H stretch fundamentals (2970-3370 cm(-1)). The C3H3--N-2 dimers are produced in an electron impact cluster ion source by supersonically expanding a gas mixture of allene, N-2, and Ar. Rovibrational analysis of the spectra demonstrates that (at least) two C3H3+ isomers are produced in the employed ion source, namely the cyclopropenyl (c-C3H3+) and the propargyl (H2CCCH+) cations. This observation is the first spectroscopic detection of the important c-C3H3+ ion in the gas phase. Both C3H3+ cations form intermolecular proton bonds to the N-2 ligand with a linear -C-H...N-N configuration, leading to planar C3H3+-N-2 structures with C-2v symmetry. The strongest absorption of the H2CCCH+-N-2 dimer in the spectral range investigated corresponds to the acetylenic C-H stretch fundamental (v(1) = 3139 cm(-1)), which experiences a large red shift upon N-2 complexation (Deltav(1) approximate to -180 cm(-1)). For c-C3H3+-N-2, the strongly IR active degenerate antisymmetric stretch vibration (v(4)) of c-C3H3+ is split into two components upon complexation with N-2: v(4)(a(1)) = 3094 cm(-1) and v(4)(b(2)) = 3129 cm(-1). These values bracket the yet unknown v(4) frequency of free c-C3H3+ in the gas phase, which is estimated as 3125 +/- 4 cm(-1) by comparison with theoretical data. Analysis of the nuclear spin statistical weights and A rotational constants of H2CCCH+-N-2 and c-C3H3+-N-2 provide for the first time high-resolution spectroscopic evidence that H2CCCH+ and c-C3H3+ are planar ions with C-2v and D-3h symmetry, respectively, Ab initio calculations at the MP2(full)/6-311G(2df,2pd) level confirm the given assignments and predict intermolecular separations of R-e = 2.1772 and 2,0916 Angstrom and binding energies of D-e = 1227 and 1373 cm(-1) for the H-bound c-C3H3+-N-2 and H2CCCH+-N-2 dimers, respectively.