A high performance block coded modulation technique using a concatenated phase/frequency signal constellation is introduced. The coded modulation schemes described have very large minimum squared Euclidean distance (MSED) and are bandwidth efficient with reference to uncoded QPSK, giving gains of up to 15 dB over the AWGN channel. Simulation results are presented over AWGN and fading channels. An appropriate mapping of an encoder to a partitioned constellation will increase the MSED of a coded modulation scheme and thus improve the error performance. Using a phase/frequency modulation technique which produces signals varying both in phase and frequency, we describe a method to expand such a modulation scheme from four to eight dimensions, and-using a single parity check (SPC) code-provide a new modulation scheme with increased MSED. This new modulation scheme is then combined with RS codes over GF(128) to construct bandwidth efficient coding schemes giving large coding gains.