A suite of paddle-wheel shaped [Cu2(PymPPh2)3(Lan)n](PF6)2 complexes showing efficient thermally activated delayed fluorescence (TADF) has been synthesized. In these complexes, Cu(I) ions are P,N-bridged by three diphenyl(2-pyrimidyl)phosphine (PymPPh2, L) ligands in a "head-to-tail" fashion, and one or both metals are also capped by the ancillary ligand (Lan = MeOH, Me2CO, MeCN, PhCN). At ambient temperature, the solid complexes emit TADF with the quantum yield of up to 85% and the lifetimes of from 9.6 to 27 μs. The ancillary ligands, whose orbitals negligibly contribute to the radiative 1(M + L + Lan)LCT state, remarkably adjust emission energies and ΔE(S1-T1) energy splitting magnitudes of the emitters obtained. Thus, depending on structure and/or number of the Lan molecules, the emission maxima vary from 500 to 563 nm, and the ΔE(S1-T1) gaps range 550-1100 cm-1. Such tunable TADF characteristics coupled with the excellent solubility and air-stability make the complexes presented to be promising TADF materials.