Based on the versatile combination of PbQ- and Bi2Q3-type (Q = S, Se, Te) fragments, we explored new compounds in the Pb/Bi/Se ternary system. The new class of compounds, Pb5Bi6Se14, Pb5Pb12Se23, and PbBi8Se13 are homologues with different combination of alternating Bi2Se3- and PbSe-type layers. α- and β-Pb6Bi2Se9 were obtained in different synthetic conditions and the former is isostructural to heyrovskyite (Pb6Bi2S9) while the latter is a NaCl-type cubic phase. Pb5Bi6Se14 shows a power factor of 11.2 μW/cm·K2 with electrical conductivity of 657 S/cm and thermopower of -131 μV/K at 271 K. The most significant characteristic of this material is the extremely low thermal conductivity of less than 1.0 W/m·K at room temperature. On the basis of these properties, a preliminary doping study for Pb5Bi6Se14 with Sn, Sb, and SbBr3 as dopants was undertaken and the results are presented in this report.