A specially designed flow cell was used to investigate birefringence in transient shear flow, Deltan(+)((gamma) over dot, t), of three semiflexible main-chain thermotropic liquid-crystalline polymers (TLCPs), poly[(x)-p-phenylene 1,10-decamethylenebis(4-oxybenzoate)] (PxHQ10) with varying pendant side groups (x = oxyethyleneethoxy, tert-butyl, or phenylsulfonyl). Also, shear rheometry was used to investigate the growth of shear stress sigma (+)((gamma) over dot, t) and first normal stress difference N-1(+)((gamma) over dot, t) during transient shear flow of the same TLCPs. Upon startup of shear flow, Deltan(+)((gamma) over dot, t) initially increases rapidly, follows two minor overshoots, and then levels off to attain a steady-state value Deltan in all three TLCPs. The steady-state value of Deltan for PSHQ10 (PxHQ10 with x = phenylsulfonyl pendant side group) was found to be greater than that for PEHQ10 (PxHQ10 with x = ethoxy pendant side group) and PTHQ10 (PxHQ10 with x = tert-butyl pendant side group). This behavior is strongly correlated to the large van der Waals volume of phenylsulfonyl pendant side groups in PSHQ10 compared to that of ethoxy pendant side groups in PEHQ10 and tert-butyl pendant side groups in PTHQ10. It is also observed that N-1(+)((gamma) over dot, t) exhibits a very large overshoot followed by an oscillatory decay to attain a steady-state value N-1, while sigma (+)((gamma) over dot, t) shows a very large overshoot followed by a rapid monotonic decrease to attain a steady-state value, sigma. The peak values of N-1(+)((gamma) over dot, t) and sigma (+)((gamma) over dot, t) for PSHQ10 were found to be 3-4 times greater than those for both PEHQ10 and PTHQ10, which we again attribute to the bulky phenylsulfonyl pendant side groups in PSHQ10. Only positive values of N-1(+)((gamma) over dot, t) and N-1 were observed over the entire range of shear rates investigated. Variations of the ratio N-1(+)((gamma) over dot, t)/sigma (+)((gamma) over dot, t) with shear strain ((gamma) over dot t) were found to be very similar to variations of Deltan(+)((gamma) over dot, t) with (gamma) over dot t for all three TLCPs investigated, except for that the ratio N-1(+)((gamma) over dot, t)/sigma (+)((gamma) over dot, t) reached a steady state sooner than Deltan(+)((gamma) over dot, t). In steady-state shear flow, it is observed that the ratio N-1/sigma overlaps Lambdan over the entire range of temperatures investigated; specifically, both the ratio N-1/sigma and Deltan remain constant at temperatures far below the clearing temperature (T-NI), decrease gradually as the temperature approaches T-NI, and drop precipitously to zero value at and near T-NI.