A series of novel phospholium amphiphilic compounds with straight alkyl chains with different numbers of carbon atoms (12,14,15,16,17,18) were synthesized. The quaternary phosphorus, phosphonium cation, is incorporated into a five-membered heterocyclic ring. Their physicochemical properties were investigated by measurements of surface tension, conductivity and dynamic light scattering. The critical micelle concentration (c M ), the surface tension value at the c M (c cmc ), the surface area at the surface saturation per head group (A cmc ), the ionization degree of micelle (a), the free energy of micellization (DG°m ic ), and hydrodynamic diameter (d h ) were determined. Antimicrobial activity was tested against bacteria and yeast. The structure-activity relationship was determined. 3 J CP = 17.3 Hz, = C-CH 3 ) 22.5 (d, 1 J CP = 46.2 Hz, a CH 2 of alkyl chain), 22.6 (d, 2 J CP = 4.1 Hz, b CH 2 of alkyl chain), 22.7 (x CH 2 of alkyl chain), 29.1, 29.3, 29.4, 29.5, 29.6(0), 29.6(4), 29.7 (d-x-2 CH 2 of alkyl chain), 30.5 (d, 3 J CP = 15.6 Hz, c CH 2 of alkyl chain), 31.9 (x-1 CH 2 of alkyl chain), 113.6 (d, 1 J CP = 80.0 Hz, = CHP), 115.9 (d, 1 J CP = 83.9 Hz, Ph C 1 ), 130.0 (d, 3 J CP = 12.9 Hz, Ph C meta ), 133.6 (d, 2 J CP = 10.7 Hz, Ph C ortho ), 134.6 (d, 4 J CP = 3.0 Hz, Ph C para ), 163.2 (d, 2 J CP = 16.4 Hz, = C-CH 3 ); 31 P NMR (CDCl 3 , H 3 PO 4 ) d: 38.5; IR t max /cm -H NMR (CDCl 3 , TMS) d: 0.88 (t, 3 J H,H = 6.7 Hz, 3H, CH 3 of alkyl chain), 1.13-1.38 (m, 22H, 11 9 CH 2 of alkyl chain), 1.38-1.62 (m, 4H, b, c CH 2 of alkyl chain) 2.29 (s, 6H, 2 9 = C-CH 3 ), 3.08-3.22 (m, 2H, a CH 2 of alkyl chain), 7.08 (d, 2 J HP = 30.9 Hz, 2H, = CHP), 7.54-7.61 (m, 2H, Ph H meta ), 7.61-7.75 (m, 1H, Ph H para ), 8.15-8.23 (m, 2H, Ph H ortho ); 13 C NMR (CDCl 3 , TMS) d: 14.1 (CH 3 of alkyl chain), 18.5 (d, 3 J CP = 17.3 Hz, = C-CH 3 ) 22.5 (d, 1 J CP = 46.1 Hz, a CH 2 of alkyl chain), 22.6 (d, 2 J CP = 4.1 Hz, b CH 2 of alkyl chain), 22.7 (x CH 2 of alkyl chain), 29.1, 29.3, 29.4, 29.5, 29.6, 29.7 (d-x-2 CH 2 of alkyl chain), 30.5 (d, 3 J CP = 15.4 Hz, c CH 2 of alkyl chain), 31.9 (x-1 CH 2 of alkyl chain), 113.6 (d, 1 J CP = 80.0 Hz, = CHP), 115.8 (d, 1 J CP = 83.8 Hz, Ph C 1 ), 130.0 (d, 3 J CP = 12.9 Hz, Ph C meta ), 133.5 (d, 2 J CP = 10.4 Hz, Ph C ortho ), 134.7 (d, 4 J CP = 3.0 Hz, Ph C para ), 163.2 (d, 2 J CP = 16.5 Hz, = C-CH 3 ); 31 P NMR (CDCl 3 , H 3 PO 4 ) d: 38.5; IR t max /cm -