By reacting P 4 Se 3 and As 4 S 3 with Ag[Al(OR F ) 4 ] {-R F = -C(CF 3 ) 3 or -hfip [= -C(H)(CF 3 ) 2 ]} in suitable solvents, (5) were synthesized and characterized by SC-XRD, Mass spectrometry, Raman spectroscopy as well as solution NMR spectroscopy. When using stronger coordinating anions, only P 4 Se 3 forms an isolable complex yielding 1 featuring a [Ag 2 (P 4 Se 3 ) 2 ] 2+ core capped by anions acting as the first example of P 4 Se 3 coordinating through selenium atoms. Upon using the weakly coordinating anion [Al{OC(CF 3 ) 3 } 4 ] -, the dimeric complexes 2 and 4 are accessible in dichloromethane or ortho-difluorobenzene (o-dfb), respectively. Complex 2 shows isolated [Ag 2 (P 4 Se 3 ) 4 - [a] Computational Details: All computations were performed by using the program package TURBOMOLE 7.1. [38] All investigated molecular structures were optimized using the functionals BP86 [39] (with RI approximation [40] ) and together with the basis sets def-SV(P). [41] A fine integration grid (m4) and the default SCF convergence criteria (10 -6 a.u.) were used. The vibrational frequencies of all assessed species were computed with the implemented module AOFORCE [42] and checked for minima (no imaginary frequencies).Preparation of P 4 Se 3 : P 4 Se 3 was obtained by heating stoichiometric amounts of grey selenium and white phosphorus in tetraline followed by extraction and recrystallization in CS 2 , following the literature procedure. [43] FT-Raman: ν = 135 (vw), 214 (m), 317 (sh), 324 (vw), 346 (sh), 365 (vs), 370 (sh), 405 (vw), 484 (w) cm -1 . NMR: 31 P NMR (122 MHz, CS 2 , r.t.): δ = -104.6 [d, 3 P basal , 2 J(P basal , P apical ) = 72 Hz], 37.4 [q, 1 P apical , 2 J(P basal , P apical ) = 72 Hz] ppm. 77 Se (57 MHz, CS 2 , r.t.): δ = 763.3 (m, P 4 77 SeSe 2 ) ppm. 31 P NMR (162 MHz, CD 2 Cl 2 , r.t.): δ = -114.1 [d, 3 P basal , 2 J(P basal , P apical ) = 72 Hz], 30.5 [q, 1 P apical , 2 J(P basal , P apical ) = 72 Hz] ppm. 31 P NMR (162 MHz, SO 2 , r.t.): δ = -113.7 [d, 3 P basal , 2 J(P basal , P apical ) = 72 Hz], 29.6 [q, 1 P apical , 2 J(P basal , P apical ) = 72 Hz] ppm. Mass Spectra: (ASAP, Source Voltage 25 V, Source Offset 25 V, Temperature 400°C, positive): m/z = 173 [P 3 80 Se] + , 365 [HP 4 80 Se 3 ] + .Preparation of As 4 S 3 : As 4 S 3 was obtained by melting stoichiometric amount of the elements for five days at 420°C, followed by Soxhlet-extraction with toluene. FT-Raman: ν = 145 (vw), 172 (w), 186 (m), 207 (m), 217 (m), 230 (sh), 273 (vs), 338 (sh), 359 (m), 375 (vw) cm -1 . Mass Spectra: (ASAP, Source Voltage 25 V, Source Offset 25 V, Temperature 400°C, positive): m/z = 257 [As 3 32 S] + , 289 [As 3 32 S 2 ] + , 321 [As 3 32 S 3 ] + , 396 [As 4 32 S 3 ] + , 397 [HAs 4 32 S 3 ] + , 428 [As 4 32 S 4 ] + , 429 [HAs 4 32 S 4 ] + .