  The wideband timing technique enables the high-precision simultaneous
estimation of pulsar Times of Arrival (ToAs) and Dispersion Measures (DMs)
while effectively modeling frequency-dependent profile evolution. We present
two novel independent methods that extend the standard wideband technique to
handle simultaneous multi-band pulsar data incorporating profile evolution over
a larger frequency span to estimate DMs and ToAs with enhanced precision. We
implement the wideband likelihood using the libstempo python interface to
perform wideband timing in the tempo2 framework. We present the application of
these techniques to the dataset of fourteen millisecond pulsars observed
simultaneously in Band 3 (300 - 500 MHz) and Band 5 (1260 - 1460 MHz) of the
upgraded Giant Metrewave Radio Telescope (uGMRT) with a large band gap of 760
MHz as a part of the Indian Pulsar Timing Array (InPTA) campaign. We achieve
increased ToA and DM precision and sub-microsecond root mean square post-fit
timing residuals by combining simultaneous multi-band pulsar observations done
in non-contiguous bands for the first time using our novel techniques.
