Aminobenzothiazole‐functionalised phosphane 1 and its corresponding phosphorus(V) analogues 2–4 were synthesised in high yields. New 1D polymeric salts K[ClC6H3NC(S)NP(E)Ph2]∞ (E = O 5; E = S 6) were shown, by using single‐crystal X‐ray diffraction, to exhibit unique potassium metal ion coordination through either κ3‐N2O tridentate (E = O) or κ2‐N2 bridging (E = S) modes. In contrast, κ2‐NE chelation (E = S, Se) was observed upon complexation to a range of metal fragments including {Ir(η5‐Cp*)Cl} (E = S 8; E = Se 9), {Rh(η5‐Cp*)Cl} (E = S 10; E = Se 11), {Ru(η6‐p‐MeC6H4iPr)Cl} (E = S 12), {Ru(η6‐C6Me6)Cl} (E = S 13) and {Pt(PMe2Ph)Cl} (E = S 14). All new compounds were characterised by a combination of multinuclear NMR, FTIR and microanalysis. Seven compounds were structurally characterised by using single‐crystal X‐ray crystallography.