Simultaneous measurements of effective thermal conductivity (lambda(e)) and effective thermal diffusivity (x(e)) of twin pellets of ZnxSe100-x (x = 10, 20, 40 and 50) chalcogenide materials, prepared under a load of 5 tons (equivalent pressure approximate to 433 MPa), have been made at room temperature using transient plane source (TPS) technique. From the measured values of lambda(e) and x(e) specific heat per unit volume (C-p) has been calculated. The results indicate that both the values of lambda(e) and x(e) increase linearly with increasing Zn concentration. Similar to lambda(e) and x(e) the C-p also shows a linear increase with the increase in Zn concentration. This behaviour of lambda(e) and Z with increasing Zn concentration can be explained using structural information obtained from X-ray diffraction (XRD) of these materials and also using the change in the nature of bond from covalent to iono-covalent in this system. Comparative XRD studies for structural investigation of ZnxSe100-x(x = 10 and 40) have also been discussed. An effort has also been made to predict these values by an empirical relation. The values obtained through empirical relations are in good agreement with the experimental values of lambda(e), x(e), and calculated values of C-p. (c) 2005 Published by Elsevier B.V.