The new indium(II, III)‐oxidephosphate In2O(PO4) has been obtained from In2O3 and phosphorus (n(In) : n(P) = 1 : 0.53, 800 °C, iodine as mineralizer; In2O3 and indium as by products). Colourless single crystals of In2O(PO4) were grown by chemical vapour transport in a temperature gradient (800 → 700 °C) using iodine as transport agent. The crystal structure of In2O(PO4) ($P{\bar 1}$, Z = 2, a = 5.220(3) Å, b = 6.322(3) Å, c = 6.789(3) Å, α = 107.72(5)°, β = 109.21(5)°, γ = 95.56(6)°, is characterised by a three‐dimensional network of [PO4] tetrahedra and [In2O10] groups formed by edge‐sharing octahedra [In3+O6]. Channels within the network (∥ crystallographic b‐axis) contain (In—In)4+ dimers in agreement with the formula (In2)4+(In3+)2O2(PO4)2. IR‐ and Raman‐spectra have been measured to characterise the In‐In bond. The strongest emission in the Raman spectrum at $\tilde {\nu}$ = 163 cm‐1 is attributed to the In‐In stretching vibration. For In3(PO4)2 [structural formula: (In2)4+3(PO4)4] $\tilde {\nu}$‐(In—;In) = 195 cm‐1 is observed.