Researches on multifunctional molecular materials with both nonlinear optical activity and fluorescence properties have received much interest in molecular chemistry since they have wide application prospects. Here a novel ionic compound 2(BPP)⁺·[Mn(NCS)₄]^2- (1) was synthesized via the assembly of benzyltriphenylphosphorus chloride, isothiocyanate and manganese chloride, which displays both strong SHG response and purple luminescence. Compound 1 belongs to monoclinic system and crystallizes in Cc space group. X-ray single-crystal diffraction analysis shows that Mn²⁺ ions are tetra-coordinated with N atoms of four NCS^- ions through forming a distorted tetrahedral configuration. The anion Mn(NCS)₄^2- forms a 1D chain structure through strong S···S interaction. At the same time, there are abundant C–H···S and π···π interactions, which further accumulate into a three-dimensional supramolecular structure. Solid-state fluorescence studies show that the complex 1 has strong purple fluorescence with emission wavelength of 396 nm under excitation wavelength 248 nm. In particular, the second harmonic generation (SHG) measurements show that compound 1 has nonlinear optical activity and its SHG response is 2.25 times that of standard potassium dihydrogen phosphate (KDP). This multifunctional molecular material with SHG response and purple fluorescence is of great significance for the development of new metal organic complexes with potential application prospects.