The selenium centers of [Pt 2 (µ-Se) 2 (PPh 3 ) 4 ] are subject to electrophilic attack from various organic halides. Reactions with MeI, n-BuCl, R,R′-dichloro-p-xylene, andand [Pt 2 (µ-SeCH 2 C 6 H 4 CH 2 Se)(PPh 3 ) 4 ] 2+ , respectively, preserving the dinuclear core and giving rise to new selenium-derivatized ligand complexes. Reaction with oxalyl chloride gives [Pt(η 2 -Se 2 C 2 O 2 -Se,Se′)(PPh 3 ) 2 ], leading to the disintegration of the core to a mononuclear complex supported by a new chelating selenium donor ligand. Reactions with malonyl chloride and succinyl chloride give [(COCH 2 COCl)Se] 2 and [(COCH 2 CH 2 COCl)Se] 2 respectively, leading to complex disintegration and liberation of new selenium materials. The crystal structures of the aggregates [Pt 2 (µ-Se)(µ-SeMe)(PPh 3 ) 4 ][PF 6 ], [Pt 2 (µ 3 -Se) 2 (PPh 3 ) 4 -(CH 2 C 6 H 4 CH 2 )][PF 6 ] 1.25 [Cl] 0.75 , and [Pt(η 2 -Se 2 C 2 O 2 -Se,Se′)(PPh 3 ) 2 ] are described. The potential of using [Pt 2 (µ-Se) 2 (PPh 3 ) 4 ] as a source for metal-assisted synthesis of new and unusual organoselenium compounds is discussed.